Encoding and measurement

Creation, detection, and decoherence of macroscopic quantum superposition states in double-well Bose-Einstein condensates

We study the possibility of creating many-particle macroscopic quantum superposition (Schrödinger cat)–like states by using a Feshbach resonance to reverse the sign of the scattering length of a Bose-Einstein condensate trapped in a double-well potential. To address the issue of the experimental verification of coherence in the catlike state, we study the revival of the initial condensate state in the presence of environmentally induced decoherence. As a source of decoherence, we consider the interaction between the atoms and the electromagnetic vacuum, due to the polarization induced by an incident laser field. We find that the resulting decoherence is directly related to the rate at which spontaneously scattered photons carry away sufficient information to distinguish between the two atom distributions which make-up the cat state. We show that for a “perfect” cat state, a single scattered photon will bring about a …

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.73.023606

YP Huang, MG Moore

Optical sum-frequency generation in a whispering-gallery-mode resonator

We demonstrate sum-frequency generation between a telecom wavelength and the Rb D2 line, achieved through natural phase matching in a nonlinear whispering gallery mode resonator. Due to the strong optical field confinement and ultra high Q of the cavity, the process saturates already at sub-mW pump peak power, at least two orders of magnitude lower than in existing waveguide-based devices. The experimental data are in agreement with the nonlinear dynamics and phase matching theory based on spherical geometry. Our experimental and theoretical results point toward a new platform for manipulating the color and quantum states of light waves for applications such as atomic memory based quantum networking and logic operations with optical signals.

https://iopscience.iop.org/article/10.1088/1367-2630/16/5/053025/meta

DV Strekalov, AS Kowligy, YP Huang, P Kumar

Quantum parametric mode sorting: Beating the time-frequency filtering

Selective detection of signal over noise is essential to measurement and signal processing. Time-frequency filtering has been the standard approach for the optimal detection of non-stationary signals. However, there is a fundamental tradeoff between the signal detection efficiency and the amount of undesirable noise detected simultaneously, which restricts its uses under weak signal yet strong noise conditions. Here, we demonstrate quantum parametric mode sorting based on nonlinear optics at the edge of phase matching to improve the tradeoff. By tailoring the nonlinear process in a commercial lithium-niobate waveguide through optical arbitrary waveform generation, we demonstrate highly selective detection of picosecond signals overlapping temporally and spectrally but in orthogonal time-frequency modes as well as against broadband noise, with performance well exceeding the theoretical limit of the …

https://www.nature.com/articles/s41598-017-06564-7

A Shahverdi, YM Sua, L Tumeh, YP Huang

Mode-resolved photon counting via cascaded quantum frequency conversion

Resources for the manipulation and measurement of high-dimensional photonic signals are crucial for implementing qudit-based applications. Here we propose potentially high-performance, chip-compatible devices for such purposes by exploiting quantum frequency conversion in nonlinear optical media. Specifically, by using sum-frequency generation in a χ^(2) waveguide, we show how mode-resolved photon counting can be accomplished for telecom-band photonic signals subtending multiple temporal modes. Our method is generally applicable to any nonlinear medium with arbitrary dispersion properties.

https://opg.optica.org/abstract.cfm?uri=ol-38-4-468

YP Huang, P Kumar

Quantum optical arbitrary waveform manipulation and measurement in real time

We describe a technique for dynamic quantum optical arbitrary-waveform generation and manipulation, which is capable of mode selectively operating on quantum signals without inducing significant loss or decoherence. It is built upon combining the developed tools of quantum frequency conversion and optical arbitrary waveform generation. Considering realistic parameters, we propose and analyze applications such as programmable reshaping of picosecond-scale temporal modes, selective frequency conversion of any one or superposition of those modes, and mode-resolved photon counting. We also report on experimental progress to distinguish two overlapping, orthogonal temporal modes, demonstrating over 8 dB extinction between picosecond-scale time-frequency modes, which agrees well with our theory. Our theoretical and experimental progress, as a whole, points to an enabling optical technique for …

https://opg.optica.org/abstract.cfm?uri=oe-22-23-27942

AS Kowligy, P Manurkar, NV Corzo, VG Velev, M Silver, RP Scott, ...

Experimental demonstration of interaction-free all-optical switching via the quantum Zeno effect

We experimentally demonstrate all-optical interaction-free switching using the quantum Zeno effect, achieving a high contrast of 35∶ 1. The experimental data match a zero-parameter theoretical model for several different regimes of operation, indicating a good understanding of the switch’s characteristics. We also discuss extensions of this work that will allow for significantly improved performance, and the integration of this technology onto chip-scale devices, which can lead to ultra-low-power all-optical switching, a long-standing goal with applications to both classical and quantum information processing.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.110.240403

KT McCusker, YP Huang, AS Kowligy, P Kumar

Antiparity-time symmetry in passive nanophotonics

Parity-time (PT) symmetry in non-Hermitian optical systems promises distinct optical effects and applications not found in conservative optics. Its counterpart, anti-PT symmetry, subscribes another class of intriguing optical phenomena and implies complementary techniques for exotic light manipulation. Despite exciting progress, so far, anti-PT symmetry has only been realized in bulky systems or with optical gain. Here, we report an on-chip realization of non-Hermitian optics with anti-PT symmetry by using a fully passive, nanophotonic platform consisting of three evanescently coupled waveguides. By depositing a metal film on the center waveguide to introduce strong loss, an anti-PT system is realized. Using microheaters to tune the waveguides’ refractive indices, striking behaviors are observed such as equal power splitting, synchronized amplitude modulation, phase-controlled dissipation, and transition from anti …

https://pubs.acs.org/doi/abs/10.1021/acsphotonics.0c01053

H Fan, J Chen, Z Zhao, J Wen, YP Huang

Direct generation and detection of quantum correlated photons with 3.2 um wavelength spacing

Quantum correlated, highly non-degenerate photons can be used to synthesize disparate quantum nodes and link quantum processing over incompatible wavelengths, thereby constructing heterogeneous quantum systems for otherwise unattainable superior performance. Existing techniques for correlated photons have been concentrated in the visible and near-IR domains, with the photon pairs residing within one micron. Here, we demonstrate direct generation and detection of high-purity photon pairs at room temperature with 3.2 um wavelength spacing, one at 780 nm to match the rubidium D2 line, and the other at 3950 nm that falls in a transparent, low-scattering optical window for free space applications. The pairs are created via spontaneous parametric downconversion in a lithium niobate waveguide with specially designed geometry and periodic poling. The 780 nm photons are measured with a silicon …

https://www.nature.com/articles/s41598-017-17820-1

YM Sua, H Fan, A Shahverdi, JY Chen, YP Huang

Interaction-free all-optical switching in χ(2)microdisks for quantum applications

We propose a quantum switch for telecom-band applications that is composed of a χ^(2) microdisk coupled to two fibers (or waveguides). The idea is to apply a pump pulse to shift the microdisk out of resonance, thereby switching the device between the cross and bar states in an interaction-free manner. As an example, a 2.5-μm-thick, 10μm radius GaAs microdisk with an intrinsic Q of ∼10^8 and a fiber-cavity-coupling Q of ∼10^4 can achieve low-loss (≲1%) switching for gigahertz-rate O-band quantum signals with milliwatt-peak-power pumps in the C band.

https://opg.optica.org/abstract.cfm?uri=ol-35-14-2376

YP Huang, P Kumar

Optimized double-well quantum interferometry with Gaussian squeezed states

A Mach-Zender interferometer with a Gaussian number-difference squeezed input state can exhibit sub-shot-noise phase resolution over a large phase interval. We derive the optimal level of squeezing for a given phase interval Δ θ 0 and particle number N. We then propose an adaptive measurement sequence in which the amount of squeezing is increased with each measurement. With this scheme, any phase on (− Δ θ 0, Δ θ 0) can be measured with a precision of 3.5/N, requiring only 2–4 measurements, provided only that N tan(Δ θ 0)< 10 40. In a double-well Bose-Einstein condensate, the optimized input states can be created by adiabatic manipulation of the ground state.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.250406

YP Huang, MG Moore

Quantum frequency conversion in nonlinear microcavities

We study nonlinear microresonantors as potential implements for quantum frequency conversion of narrowband optical signals. Using silicon-nitride microdisks as a concrete example, we show that high-conversion performance can be achieved with relatively low pump power. Being chip integratable, such devices hold promise for use in large-scale quantum applications, including atomic-memory-based quantum repeaters.

https://opg.optica.org/abstract.cfm?uri=ol-38-12-2119

YP Huang, V Velev, P Kumar

Heralding single photons without spectral factorability

Recent efforts to produce single photons via heralding have relied on creating spectrally factorable two-photon states in order to achieve both high purity and high production rate. Through a careful multimode analysis, we find, however, that spectral factorability is not necessary. Utilizing single-mode detection, a similar or better performance can be achieved with nonfactorable states. This conclusion rides on the fact that even when using a broadband filter, a single-mode measurement can still be realized, as long as the coherence time of the triggering photons exceeds the measurement window of the on-off detector.

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.82.043826

YP Huang, JB Altepeter, P Kumar

Antibunched emission of photon pairs via quantum zeno blockade

We propose a new methodology, namely, the “quantum Zeno blockade,” for managing light scattering at a few-photon level in general nonlinear-optical media, such as crystals, fibers, silicon microrings, and atomic vapors. Using this tool, antibunched emission of photon pairs can be achieved, leading to potent quantum-optics applications such as deterministic entanglement generation without the need for heralding. In a practical implementation using an on-chip toroidal microcavity immersed in rubidium vapor, we estimate that high-fidelity entangled photons can be produced on-demand at MHz rates or higher, corresponding to an improvement of≳ 10 7 times from the state-of-the-art.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.108.030502

YP Huang, P Kumar

Interaction-Free Quantum Optical Fredkin Gates inMicrodisks

We present novel “interaction-free” realizations of quantum optical Fredkin gates that do not rely on direct physical coupling between the target light (signal) and the control light (pump). The interaction-free feature of such gates allow to overcome the fundamental limits of photon loss and quantum-state decoherence imposed by the signal-pump coupling. This advantage, together with the low inherent quantum-noise level in χ (2) microdisks, gives rise to substantially improved performance over the existing Fredkin-gate designs. Explicitly using lithium-niobate mircrodisks, we present two kinds of interaction-free Fredkin gates, a phase gate and an optical-path gate, both of which are designed with telecom-band applications in mind. For both gates, the threshold pump peak power to achieve a gate contrast >;100 and a signal loss <;10% is hundreds of microwatts for practical parameters of the devices.

https://ieeexplore.ieee.org/abstract/document/5740561/

YP Huang, P Kumar

Interaction-free all-optical switching via the quantum Zeno effect

We propose an interaction-free scheme for all-optical switching which does not rely on the physical coupling between signal and control waves. The interaction-free nature of the scheme allows it to overcome the fundamental photon-loss limit imposed by the signal-pump coupling. The same phenomenon protects photonic-signal states from decoherence, making devices based on this scheme suitable for quantum applications. Focusing on χ (2) waveguides, we provide device designs for traveling-wave and Fabry-Perot switches. In both designs, the performance is optimal when the signal switching is induced by coherent dynamical evolution. In contrast, when the switching is induced by a rapid dissipation channel, it is less efficient.

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.82.063826

YP Huang, JB Altepeter, P Kumar

Optimized heralding schemes for single photons

A major obstacle to a practical, heralded source of single photons is the fundamental trade-off between high purity and high production rate. To overcome this difficulty, we propose applying sequential spectral and temporal filtering on the signal photons before they are detected for heralding. Based on a multimode theory that takes into account the effect of simultaneous multiple photon-pair emission, we find that these filters can be optimized to yield both high purity and a high production rate. While the optimization conditions vary depending on the underlying photon-pair spectral correlations, all correlation profiles can lead to similarly high performance levels when optimized filters are employed. This suggests that a better strategy for improving the performance of heralded single-photon sources is to adopt an appropriate measurement scheme for the signal photons, rather than tailoring the properties of the photon …

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.84.033844

YP Huang, JB Altepeter, P Kumar

Ultra-wideband and high-gain parametric amplification in telecom wavelengths with an optimally mode-matched PPLN waveguide

We report a wideband optical parametric amplification (OPA) over 14 THz covering telecom S, C, and L bands with observed maximum parametric gain of 38.3 dB. The OPA is realized through cascaded second-harmonic generation and difference-frequency generation (cSHG-DFG) in a 2 cm periodically poled LiNbO_3 (PPLN) waveguide. With tailored cross section geometry, the waveguide is optimally mode matched for efficient cascaded nonlinear wave mixing. We also identify and study the effect of competing nonlinear processes in this cSHG-DFG configuration.

https://opg.optica.org/abstract.cfm?uri=ol-43-12-2965

YM Sua, JY Chen, YP Huang

Mode selective up-conversion detection for LIDAR applications

We study mode selective up-conversion detection as a viable approach to improving signal-to-noise and ranging resolution in LIDAR applications. It involves pumping a nonlinear waveguide at the edge of phase matching with picosecond pulses, so that only the backscattered signal photons in a single or few desirable time-frequency modes are efficiently up-converted while the broadband background noise in all other modes is rejected. We demonstrate a 41-dB increase in the signal-to-noise ratio for single-photon counting compared to that of direct detection using a commercial InGaAs single-photon detector, while achieving sub-millimeter ranging resolution with few detected photons. The proposed technique implies new LIDAR capabilities for ranging and imaging.

https://opg.optica.org/abstract.cfm?uri=oe-26-12-15914

A Shahverdi, YM Sua, I Dickson, M Garikapati, YP Huang

Lossless single-photon shaping via heralding

Using spontaneous optical parametric downconversion, we experimentally demonstrate heralded generation of shaped single photons, whose modes are tailored indirectly by applying amplitude modulation on the pump field that drives the downconversion process. Our experiment opens a door to creating high-quality, mode-shaped single photons at a substantially higher efficiency than is possible with the existing method of direct single-photon shaping.

https://opg.optica.org/abstract.cfm?uri=ol-36-9-1674

KG Köprülü, YP Huang, GA Barbosa, P Kumar

Mode-selective image upconversion

We study selective upconversion of optical signals according to their detailed transverse electromagnetic modes and demonstrate its proof of operation in a nonlinear crystal. The mode selectivity is achieved by preparing the pump wave in an optimized spatial profile to drive the upconversion. For signals in the Laguerre–Gaussian modes, we show that a mode can be converted with up to 60 times higher efficiency than an overlapping, but orthogonal, mode. This nonlinear optical approach may find applications in compressive imaging, pattern recognition, quantum communications, and others, where the existing linear optical methods are limited.

https://opg.optica.org/abstract.cfm?uri=ol-44-1-98

S Kumar, H Zhang, S Maruca, YP Huang

Two-qubit conditional phase gate in laser-excited semiconductor quantum dots using the quantum Zeno effect

We propose a scheme for a two-qubit conditional quantum Zeno phase gate for semiconductor quantum dots. The proposed system consists of two charged dots and one ancillary neutral dot driven by a laser pulse tuned to the exciton resonance. The primary decoherence mechanism is phonon-assisted exciton relaxation, which can be viewed as continuous monitoring by the environment. Because of the Zeno effect, a strong possibility of emission is sufficient to strongly modify the coherent dynamics, with negligible probability of actual emission. We solve analytically the master equation and simulate the dynamics of the system using a realistic set of parameters. In contrast to standard schemes, larger phonon relaxation rates increase the fidelity of the operations.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.103.037401

KJ Xu, YP Huang, MG Moore, C Piermarocchi

Distilling quantum entanglement via mode-matched filtering

We propose an avenue toward distillation of quantum entanglement that is implemented by directly passing the entangled qubits through a mode-matched filter. This approach can be applied to a common class of entanglement impurities appearing in photonic systems, where the impurities inherently occupy different spatiotemporal modes than the entangled qubits. As a specific application, we show that our method can be used to significantly purify the telecom-band entanglement generated via the Kerr nonlinearity in single-mode fibers where a substantial amount of Raman-scattering noise is concomitantly produced.

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.84.032315

YP Huang, P Kumar

Entanglement-preserving photonic switching: Full cross-bar operation with quantum data streams

As the field of quantum communications matures and adopts larger network topologies, it will require switches capable of multiplexing and demultiplexing entangled photons between network nodes. Such switches will need to operate at high speeds, with low loss, and minimal signal-band noise, while also retaining the quantum state of the routed photons. We present an all-optical, fiber-based, dual-in, dual-out switch that has a switching window of 45 ps and an insertion loss of <;3.0 dB. In addition, the switch introduces minimal degradation to the quantum state of the routed entangled photons. As a test of the switch's utility, we demultiplex a single quantum channel from a 6.5-GHz dual-channel quantum data stream. The recovered quantum state exhibits a fidelity of 96.2%±1.2% with the prepared state.

https://ieeexplore.ieee.org/abstract/document/6678557/

NN Oza, YP Huang, P Kumar

Programmable quantum random number generator without postprocessing

We demonstrate a viable source of unbiased quantum random numbers whose statistical properties can be arbitrarily programmed without the need for any postprocessing such as randomness distillation or distribution transformation. It is based on measuring the arrival time of single photons in shaped temporal modes that are tailored with an electro-optical modulator. We show that quantum random numbers can be created directly in customized probability distributions and pass all randomness tests of the NIST and Dieharder test suites without any randomness extraction. The min-entropies of such generated random numbers are measured close to the theoretical limits, indicating their near-ideal statistics and ultrahigh purity. Easy to implement and arbitrarily programmable, this technique can find versatile uses in a multitude of data analysis areas.

https://opg.optica.org/abstract.cfm?uri=ol-43-4-631

L Nguyen, P Rehain, YM Sua, YP Huang

Self-stabilized quantum optical Fredkin gate

The quantum optical Fredkin gate is an indispensable resource for networkable quantum applications. Its performance in practical implementations, however, is limited fundamentally by the inherent quantum fluctuations of the pump waves. We demonstrate a method to overcome this drawback by exploiting stimulated Raman scattering in fiber-based implementations. Using a Sagnac fiber-loop switch as a specific example, we show that high switching contrast can be maintained even in the presence of significant pump fluctuations. This unique feature of self-stabilization, together with high-speed and low-loss performance of such devices, point to a viable technology for practical quantum communications.

https://opg.optica.org/abstract.cfm?uri=ol-38-4-522

J Hu, YP Huang, P Kumar

Erasing quantum distinguishability via single-mode filtering

Erasing quantum-mechanical distinguishability is of fundamental interest and also of practical importance, particularly in subject areas related to quantum information processing. We demonstrate a method applicable to optical systems in which single-mode filtering is used with only linear optical instruments to achieve quantum indistinguishability. Through “heralded” Hong-Ou-Mandel interference experiments we measure and quantify the improvement of indistinguishability between single photons generated via spontaneous four-wave mixing in optical fibers. The experimental results are in excellent agreement with predictions of a quantum-multimode theory we develop for such systems, without the need for any fitting parameter.

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.86.033809

M Patel, JB Altepeter, YP Huang, NN Oza, P Kumar

Four-wave mixing in single-mode optical fibers

https://www.sciencedirect.com/science/article/pii/B9780123876959000123

A McMillan, YP Huang, B Bell, A Clark, P Kumar, J Rarity

Mode selective up-conversion detection with turbulence

We experimentally study a nonlinear optical approach to selective manipulation and detection of structured images mixed with turbulent noise. Unlike any existing adaptive-optics method by applying compensating modulation directly on the images, here we account for the turbulence indirectly, by modulating only the pump driving the nonlinear process but not the images themselves. This indirect approach eliminates any signal modulation loss or noise, while allowing more flexible and capable operations. Using specifically sum frequency generation in a lithium niobate crystal, we demonstrate selective upconversion of Laguerre-Gaussian spatial modes mixed with turbulent noise. The extinction reaches ~40 dB without turbulence, and maintains ~20 dB in the presence of strong turbulence. This technique could find utilities in classical and quantum communications, compressive imaging, pattern recognition, and so …

https://www.nature.com/articles/s41598-019-53914-8

H Zhang, S Kumar, YP Huang

On-demand generation of entanglement of atomic qubits via optical interferometry

The problem of on-demand generation of entanglement between single-atom qubits via a common photonic channel is examined within the framework of optical interferometry. As expected, for a Mach-Zehnder interferometer with coherent laser beam as input, a high-finesse optical cavity is required to overcome sensitivity to spontaneous emission. We show, however, that with a twin-Fock input, useful entanglement can in principle be created without cavity enhancement. Both approaches require single-photon resolving detectors, and best results would be obtained by combining both cavity feedback and twin-Fock inputs. Such an approach may allow a fidelity of 0.99 using a two-photon input and currently available mirror and detector technology. In addition, we study interferometers based on NOON states, ie, maximally entangled N-particle states, and show that they perform similarly to the twin-Fock states, yet …

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.77.032349

YP Huang, MG Moore

Super-resolution optical classifier with high photon efficiency

We propose and demonstrate a photon-efficient optical classifier to overcome the Rayleigh limit in spatial resolution. It utilizes mode-selective sum-frequency generation and single-pixel photon detection to resolve closely spaced incoherent sources based on photon counting statistics. Super-resolving and photon efficient, this technique can find applications in microscopy, light detection and ranging, and astrophysics.

https://opg.optica.org/abstract.cfm?uri=ol-45-18-4968

H Zhang, S Kumar, YP Huang

Spectrally multiplexed upconversion detection with C-band pump and signal wavelengths

We demonstrate a multiplexing scheme for upconversion-based single-photon detection using a waveguide with multiple phase-matching peaks. Two different signal wavelengths are upconverted using two distinct pump wavelengths, where all the wavelengths are in the 1550-nm band. Background photon generation rates <; 10 -4 per pulse with high internal conversion efficiencies are observed using 20-ps-long pump pulses.

https://ieeexplore.ieee.org/abstract/document/7924335/

M Silver, P Manurkar, YP Huang, C Langrock, MM Fejer, P Kumar, ...

Mode-selective frequency up-conversion in a chi (2) waveguide

We study sum-frequency generation (SFG) in a multimode PPKTP waveguide. We show that under proper quasi-phasematching, it can support one of the two scenarios. In the first, a single pump mode up-converts several different signal modes to different SFG modes. In the second, several different pairs of signal and pump modes are converted to the same SFG mode. By adjusting the relative phases and magnitudes of the pump modes, any superposition of the corresponding signal modes can be selected for up-conversion without affecting other modes, which can be used for spatial-mode de-multiplexing in both classical and quantum communications.

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8964/89640N/Mode-selective-frequency-up-conversion-in-a-chi2-waveguide/10.1117/12.2042958.short

YB Kwon, M Vasilyev

Quantum theory of all-optical switching in nonlinear Sagnac interferometers

Recently, our group demonstrated an ultrafast, low-loss, fiber-loop switch based on a nonlinear Sagnac-interferometer design, using which entangled photons were shown to be routed without any measurable degradation in their entanglement fidelity (Hall et al 2011 Phys. Rev. Lett. 106 053901). Such a device represents an enabling technology for a rich variety of networked quantum applications. In this paper, we develop a comprehensive quantum theory for such switches in general, ie those based on nonlinear Sagnac interferometers, where the in-coupling of quantum noise is carefully modeled. When applied to the fiber-loop switch, the theory shows good agreement with the experimental results without using any fitting parameter. This theory can serve as an important guiding tool for configuring switches of this kind for future quantum networking applications.

https://iopscience.iop.org/article/10.1088/1367-2630/14/5/053038/meta

YP Huang, P Kumar

Progress towards interaction-free all-optical devices

We present an all-optical control device in which coupling a weak control optical field into a high-Q lithium niobate whispering-gallery-mode microcavity decouples it from a signal field due to nonlinear optical interactions. This results in switching and modulation of the signal with low-power control pulses. In the quantum limit, the underlying nonlinear-optical process corresponds to the quantum Zeno blockade. Its “interaction-free” nature effectively alleviates loss and decoherence for the signal waves. This work therefore presents experimental progress towards acquiring large phase shifts with few photons or even at the single-photon level.

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.89.063820

DV Strekalov, AS Kowligy, YP Huang, P Kumar

Low-loss all-optical quantum switching

We present a two-input, two-output, single-photon switch prototype that is capable of achieving insertion loss <; 0.6 dB and switching speed > 5 GHz.

https://ieeexplore.ieee.org/abstract/document/6614561/

TM Rambo, K McCusker, YP Huang, P Kumar

Robust and efficient single-pixel image classification with nonlinear optics

We present a hybrid image classifier by feature-sensitive image upconversion, single pixel photodetection, and deep learning, aiming at fast processing of high-resolution images. It uses partial Fourier transform to extract the images’ signature features in both the original and Fourier domains, thereby significantly increasing the classification accuracy and robustness. Tested on the Modified National Institute of Standards and Technology handwritten digit images and verified by simulation, it boosts accuracy from 81.25% (by Fourier-domain processing) to 99.23%, and achieves 83% accuracy for highly contaminated images whose signal-to-noise ratio is only −17dB. Our approach could prove useful for fast lidar data processing, high-resolution image recognition, occluded target identification, and atmosphere monitoring.

https://opg.optica.org/abstract.cfm?uri=ol-46-8-1848

S Kumar, T Bu, H Zhang, I Huang, Y Huang

Quantum Airy photons

With exotic propagation properties, optical Airy beams have been well studied for innovative applications in communications, biomedical imaging, micromachining, and so on. Here we extend those studies to the quantum domain, creating quantum correlated photons in finite-energy Airy transverse modes via spontaneous parametric down conversion and subsequential spatial light modulation. Through two-photon coincidence measurements, we verify their Airy spatial wavefunctions, propagation along a parabolic trajectory, and that the spatial modulation does not introduce any observable degradation of quantum correlation between the photons. These results suggest the feasibility of using spatially structured photons for practically advantageous quantum applications.

https://iopscience.iop.org/article/10.1088/1361-6455/aacac5/meta

S Maruca, S Kumar, YM Sua, JY Chen, A Shahverdi, YP Huang

Carbon-dioxide absorption spectroscopy with solar photon counting and integrated lithium niobate micro-ring resonator

We demonstrate a spectroscope using single-photon counters and a chip-integrated lithium niobate micro-ring filter to measure the atmospheric CO 2 absorption spectrum passively. By thermo-optically sweeping the filter over 150 pm and referencing the resulting photon counts to a bypass channel, we sample the absorption spectrum at an ultrahigh-resolution of 6 pm. Incorporating it into a ground-based field system, we characterize the CO 2 absorption through the atmosphere by counting the solar photons across the absorption line around 1572.02 nm, which agrees well with its transmission spectrum at standard atmospheric pressure. Our results highlight the potential of adopting integrated photonics and single-photon counting in remote sensing systems for high detection sensitivity, superior resolution, and significantly reduced size, weight, and power.

https://pubs.aip.org/aip/apl/article/118/17/171103/236166

J Zhang, YM Sua, JY Chen, J Ramanathan, C Tang, Z Li, Y Hu, YP Huang

Spatial-mode-selective quantum frequency conversion in a χ (2) slab waveguide

We numerically investigate single-spatial-mode-selective up-conversion in a diffractionless χ (2) slab waveguide by optimizing its one-dimensional pump profile. Singular-value decomposition of the Green’s function predicts~ 5-dB discrimination between the first two modes’ conversion efficiencies.

https://opg.optica.org/abstract.cfm?uri=qim-2014-JW2A.52

M Vasilyev, YB Kwon, YP Huang

Selective manipulation of overlapping quantum modes

We show that spatiotemporally overlapping quantum photonic signals in orthogonal time-frequency modes can be discriminated via quantum frequency conversion during a single passage through a waveguide.

https://ieeexplore.ieee.org/abstract/document/6903026/

VG Velev, C Langrock, P Kumar, MM Fejer, YP Huang

Three-Signal Temporal-Mode Selective Upconversion Demultiplexing

We demonstrate demultiplexing of three spatio-temporally overlapped orthogonal temporal modes into three distinct wavelengths using a sum-frequency generation stage having multiple phase-matching peaks. Cross-talk between the fundamental mode and all other modes is 10 dB.

https://ieeexplore.ieee.org/abstract/document/8853284/

M Silver, YP Huang, C Langrock, MM Fejer, P Kumar, GS Kanter

Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing

Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors.

https://www.nature.com/articles/srep24344

S Shi, A Thomas, NV Corzo, P Kumar, Y Huang, KF Lee

Spatiotemporal mode-selective quantum frequency converter

We experimentally demonstrate a mode-selective quantum frequency converter over a compound spatiotemporal Hilbert space. We show that our method can achieve high extinction for high-dimensional quantum state tomography by selectively upconverting the signal modes with a modulated and delayed pump. By preparing the pump in optimized modes through adaptive feedback control, selective frequency conversion is demonstrated with up to 30 dB extinction. The simultaneous operations over high-dimensional degrees of freedom in both spatial and temporal domains can serve as a viable resource for photon-efficient quantum communications and computation.

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.104.023506

S Kumar, H Zhang, P Kumar, M Garikapati, YM Sua, YP Huang

Independent telecom-fiber sources of quantum indistinguishable single photons

Quantum-mechanically indistinguishable photons produced by independent (or equivalently, mutually phase incoherent) light sources are essential for distributed quantum information processing applications. We demonstrate heralded generation of such photons in two spatially separate telecom-fiber spools, each driven by pulsed pump waves that are measured to have no mutual phase coherence. Through Hong–Ou–Mandel experiments, we measure the quantum interference visibility of those photons to be $76.4\pm 4.2%$ $76.4 \pm 4.2$ . Our experimental results are well predicted by a quantum multimode theory we developed for such systems without the need for any fitting parameter.

https://iopscience.iop.org/article/10.1088/1367-2630/16/4/043019/meta

M Patel, JB Altepeter, YP Huang, NN Oza, P Kumar

Programmable Spatiotemporal Quantum Parametric Mode Sorter

We experimentally demonstrate a programmable parametric mode sorter of high-dimensional signals in a composite spatiotemporal Hilbert space through mode-selective quantum frequency up-conversion. As a concrete example and with quantum communication applications in mind, we consider the Laguerre-Gaussian and Hermite-Gaussian modes as the spatial and temporal state basis for the signals, respectively. By modulating the spatiotemporal profiles of the up-conversion pump, we demonstrate the faithful selection of signal photons in those modes and their superposition modes. Our results show an improvement in the quantum mode-sorting performance by coupling the up-converted light into a single-mode fiber and/or operating the up-conversion at the edge of phase matching. Optimizing pump temporal profiles allows us to achieve more than 12-dB extinction for mutually unbiased basis (MUB) sets of …

https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.19.044070

M Garikapati, S Kumar, H Zhang, YM Sua, YP Huang

Yu-Ping,“Huang,“Generation of Quantum Airy Photons,”

https://scholar.google.com/scholar?cluster=15464863346829815068&hl=en&oi=scholarr

S Kumar, S Maruca, YM Sua

Highly mode-selective quantum frequency conversion in a slab waveguide

We analyze sum-frequency generation (SFG) in a χ(2) slab waveguide with the goal of achieving a single spatial-mode operation. We first develop Green’s function formalism for the SFG equations and then perform singular-value decomposition (SVD) of the Green’s function. By adjusting the spatial profile of the pump, we manipulate the SVD spectrum to maximize the up-conversion of one signal mode while minimizing the up-conversion of all others, which opens a possibility of realizing a spatial-mode-selective quantum frequency converter for future optical communications.

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8997/89970O/Highly-mode-selective-quantum-frequency-conversion-in-a-slab-waveguide/10.1117/12.2042961.short

M Vasilyev, YB Kwon, YP Huang

Selective up-conversion of two orthogonal signal modes using shaped pump pulses

We demonstrate selective up-conversion of two orthogonal signal modes occupying the same time bin using temporally shaped pump pulses. Measured selectivities (8.4 and 4.2 dB) agree with simulation results that take device parameters into account.

https://opg.optica.org/abstract.cfm?uri=FiO-2014-FTh1B.3

P Manurkar, NV Corzo, P Kumar, GS Kanter, YP Huang

Engineering fiber-nonlinearity based entangled photon sources for quantum key distribution applications

We model fiber parametric entangled photon sources for use in quantum key distribution applications. Effects of Raman scattered photons are evaluated and are found to be manageable when appropriately detuned optical filters are employed.

https://opg.optica.org/abstract.cfm?uri=OFC-2011-OMO2

G Kanter, S Wang, YP Huang, P Kumar

Ultra-bright biphoton emission from an atomic vapor based on Doppler-free four-wave-mixing and collective emission

We propose a novel `butterfly' level scheme to generate highly correlated photon pairs from atomic vapors. With multi-photon Doppler-free pumping, background Rayleigh scattering is dipole-forbidden and collective emission is permitted in all directions. This results in usable pairs generated simultaneously in the full solid angle. Collecting these pairs can produce photon pairs at a rate of per second, given only moderate ensemble sizes of atoms.

https://arxiv.org/abs/0901.4789

YP Huang, MG Moore

Approaches, apparatuses and methods for lidar applications based on-mode-selective frequency conversion

Approaches, apparatuses and methods for LIDAR applications based on mode-selective frequency conversion are disclosed. In one embodiment, a pulse generation unit includes a mode-locked fiber laser and optical fiber bandpass filters. In the second embodiment, a LIDAR transceiver unit based on a simple, bidirectional monostatic coaxial arrangement using off-the-shelf tele-com-grade optical components includes optical fiber, fiber collimator, optical fiber circulator, optical fiber isolator and wavelength combiner. A frequency conversion detection system with single photon sensitivity includes a nonlinear optical material for frequency conversion, coupled with optimized pump pulses for efficient conversion and noise rejection, optical band pass filters for noise rejection and a single photon detection system for detecting the converted signal.

https://patents.google.com/patent/US20210116543A1/en

Y Huang, YM SUA, A SHAHVERDI

Mode-selective image upconversion through turbulence

We experimentally and numerically show the selective image up-conversion of Laguerre-Gaussian modes through turbulent noise, with potential applications in areas of image recognition and free-space optical communications.

https://opg.optica.org/abstract.cfm?uri=LS-2019-JW3A.46

H Zhang, S Kumar, YP Huang

Laser Science, JW3A. 46 1 2019

Corrigendum: Optical sum-frequency generation in a whispering-gallery-mode resonator (2015 New J. Phys. 16 053025

Corrigendum: Optical sum-frequency generation in a whispering-gallery-mode resonator (2015 New J. Phys. 16 053025) Page 1 CORRIGENDUM • OPEN ACCESS Corrigendum: Optical sum-frequency generation in a whispering-gallery-mode resonator (2015 New J. Phys. 16 053025) To cite this article: Dmitry V Strekalov et al 2015 New J. Phys. 17 099501 View the article online for updates and enhancements. You may also like Corrigendum: Inverse problems for the perturbed polyharmonic operator with coefficients in Sobolev spaces with nonpositive order (2016 Inverse Problems 32 105009) Yernat M Assylbekov - Magnetic Field of a Compact Spherical Star under f(R, T) Gravity Safiqul Islam and Shantanu Basu - Anharmonic, dimensionality and size effects in phonon transport (2017 J. Phys.: Condens. Matter 29 505703) Iorwerth O Thomas and GP Srivastava - This content was downloaded from IP address …

https://iopscience.iop.org/article/10.1088/1367-2630/17/9/099501/meta

DV Strekalov, AS Kowligy, YP Huang, P Kumar

New Journal of Physics 17 (9), 099501 1 2015

Natural phase matching in microdisk cavities

We identify new approaches to achieve natural phase matching in microdisk cavities for widely-spaced wavelengths across the visible and telecom bands.

https://opg.optica.org/abstract.cfm?uri=CLEO_AT-2014-JTh2A.72

V Velev, P Kumar, YP Huang

CLEO: Applications and Technology, JTh2A. 72 1 2014

Single-Photon Generation and Detection: Chapter 12. Four-Wave Mixing in Single-Mode Optical Fibers

The efficient generation of single photon and entangled photon states is of considerable interest both for fundamental studies of quantum mechanics and practical applications, such as quantum communications and computation. It is now well known that correlated pairs of photons suitable for such applications can be generated directly in a guided mode of an optical fiber through the nonlinear process of spontaneous four-wave mixing. Detection of one photon of the pair can be used to herald the presence of the other, in order to realise a probabilistic heralded single photon source. Alternatively, both photons can be used directly as an entangled photon pair if the source is designed such that the two photons are correlated in one or more of their degrees of freedom. This chapter provides an overview of the progress that has been made into the development of photon sources based on four-wave mixing in optical fibers. A theoretical model of four-wave mixing is described in Section 12.2, which demonstrates how the dispersion characteristics of an optical fiber influence the properties of the photon pair state that is generated. Section 12.3 focusses on heralded single photon sources operating in both the anomalous and normal dispersion regimes of optical fiber, and highlights several experimental demonstrations of this type of source. Section 12.4 discusses the concept of non-classical interference and the parameters of the generated photons that can influence the interference visibility. Section 12.5 expands upon this discussion to consider two different approaches for preparing photons in pure states that have been used to demonstrate high …

https://books.google.com/books?hl=en&lr=&id=xURzDAAAQBAJ&oi=fnd&pg=PT6&dq=info:m3cbbNowf4UJ:scholar.google.com&ots=CZBJhFj6GD&sig=f8qd2eucaOwbF3rCjIkv_OfVZPo

A McMillan, YP Huang, B Bell, A Clark, P Kumar, J Rarity

Elsevier Inc. Chapters 1 2013

Direct measurement of third-order nonlinearity of green fluorescent protein

We present the measurement of χ (3) nonlinearity of Green Fluorescent Protein. The nonlinear index is n 2= 10− 19 m 2/W, opening the possibility of using genetically engineerable and naturally occuring proteins in cells as a source of four wave mixing experiments.

https://opg.optica.org/abstract.cfm?uri=CLEO_AT-2013-JW2A.01

A Thomas, YP Huang, TM Rambo, S Shi, JB Altepeter, P Kumar

CLEO: Applications and Technology, JW2A. 01 1 2013

Ultrabright omnidirectional collective emission of correlated photon pairs from atomic vapors

Spontaneous four-wave mixing can generate highly correlated photon pairs from atomic vapors. We show that multiphoton pumping of dipole-forbidden transitions in a recoil-free geometry can result in ultrabright pair emission in the full 4 π solid angle, while strongly suppressing background Rayleigh scattering and associated atomic heating, Such a system can produce photon pairs at rates of~ 10 12 per second, given only moderate optical depths of 10− 100, or alternatively, the system can generate paired photons with subnatural bandwidths at lower production rates. We derive a rate-equation based theory of the collective atomic population and coherence dynamics and present numerical simulations for a toy model, as well as realistic model systems based on Cs 133 and Yb 171 level structures. Last, we demonstrate that dark-state adiabatic following electromagnetically induced transparency and/or time-scale …

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.81.033807

YP Huang, MG Moore

Physical Review A 81 (3), 033807 1 2010

Zeno quantum gates in semiconductor quantum dots

We propose a scheme for a two-qubit conditional phase gate by quantum Zeno effect with semiconductor quantum dots. The system consists of two charged dots and one ancillary dot that can perform Rabi oscillations under a resonant laser pulse. The quantum Zeno effect is induced by phonon-assisted exciton relaxation between the ancillary dot and the charged dots, which is equivalent to a continuous measurement. We solve analytically the master equation and simulate the dynamics of the system using a realistic set of parameters. In contrast to standard schemes, larger phonon relaxation rates increase the fidelity of the operations.

https://arxiv.org/abs/0810.4489

KJ Xu, YP Huang, MG Moore, C Piermarocchi

arXiv preprint arXiv:0810.4489 1 2008

Devices and methods for giant single-photon nonlinearities

A periodically poled microring resonator structure, a method for fabrication of the periodically poled microring resonator structure, and a method to achieve giant single-photon nonlinearity are disclosed. The strong single-photon nonlinearity in the microring resonator structure is achieved through its optimized design and fabrication procedures.

https://patents.google.com/patent/US11754908B2/en

Y Huang, J Chen

US Patent 11,754,908 2023

DEVICES AND METHODS FOR LOW VOLTAGE OPTICAL MODULATION

An electro-optic modulation structure 110, a method for fabrication of the electro-optic modulation structure, and a method of optical modulation derived from an electro-optic modulation structure with low voltage of operation are disclosed. The low voltage operation of the electro-optic modulator is realized by designed electro-optic modulation structures that include the light confining waveguide 114, overclad layer 120 and modulating electrode structure 116 for applying modulation voltages that are directed towards a low voltage operation of the electro-optic modulation 110 device upon consideration of optimal optical loss.

https://patents.google.com/patent/US20230185119A1/en

Y Huang, YM Sua, M Jin, J Chen

US Patent App. 17/923,554 2023

Spatiotemporal quantum parametric mode sorter

We demonstrate a spatio-temporal quantum parametric mode sorter that can achieve high extinction by selectively upconverting the signal modes with an optimized pump. This could serve as a viable resource for photon-efficient quantum communication and computation.

https://ieeexplore.ieee.org/abstract/document/9890186/

S Kumar, M Garikapati, H Zhang, YM Sua, YP Huang

2022 Conference on Lasers and Electro-Optics (CLEO), 1-2 2022

Devices and methods for giant single-photon nonlinearities

https://patents.google.com/patent/US20220075238A1/en

Y Huang, J Chen

US Patent App. 17/468,182 2022

Method and apparatus for quantum measurement via mode matched photon conversion

The present disclosure relates to a generally-applicable measurement technique based on coherent quantum enhancement effects and provides embodiments with nonlinear optics. The technique utilizes parametric nonlinear processes where the information-carrying electromagnetic quanta in a number of electromagnetic modes are converted phase coherently to signature quanta in a single mode or a few modes. The phase coherence means that while the quanta before conversion may have unequal or uncertain phase values across the modes, the signature quanta converted from those different modes have the (near) uniform phase. This can lead to significant increase in the signal to noise ratio in detecting weak signal buried in strong background noise. Applications can be found in remote sensing, ranging, biological imaging, field imaging, target detection and identification, covert communications, and other …

https://patents.google.com/patent/US20210156684A1/en

Y Huang

US Patent App. 17/164,551 2021

Method and apparatus for quantum measurement via mode matched photon conversion

https://patents.google.com/patent/US10935379B2/en

Y Huang

US Patent 10,935,379 2021

Observation of Anti-parity-time Symmetry on Chip

We report an on-chip realization of non-Hermitian optics with anti-Parity-Time (Anti-PT) symmetry by constructing a fully-passive, nanophotonic platform consisting of three evanescently-coupled nanowaveguides.

https://opg.optica.org/abstract.cfm?uri=FiO-2020-FTu8E.6

H Fan, J Chen, Z Zhao, J Wen, Y Huang

Frontiers in Optics, FTu8E. 6 2020

High-dimensional temporal mode propagation in a turbulent environment

Temporal modes of photonic quantum states provide a new framework to develop a robust free-space quantum key distribution (QKD) scheme in a maritime environment. We show that the high-dimensional temporal modes can be used to fulfill a persistent communication channel to achieve high photon-efficiency even in severe weather conditions. We identify the parameter regimes that allow for a high-fidelity quantum information transmission. We also examine how the turbulent environment affects fidelity and entanglement degree in various environmental settings.

https://arxiv.org/abs/1907.02321

Q Ding, R Chatterjee, Y Huang, T Yu

arXiv preprint arXiv:1907.02321 2019

Generation of Quantum Airy Photons

Airy beams have been studied for many exciting applications. Here we extend those studies to the quantum domain by creating quantum-correlated photons in Airy spatial modes and explore their potential applications.

https://opg.optica.org/abstract.cfm?uri=fio-2018-FM3C.5

S Kumar, S Maruca, YM Sua, YP Huang

Frontiers in Optics, FM3C. 5 2018

Noise tolerant LIDAR via mode selective up-conversion detection

We study mode selective up-conversion detection to improve SNR for LIDAR applications. We demonstrate a 41-dB increase in the SNR for single-photon counting compared to that of direct detection using a InGaAs single-photon detector.

https://opg.optica.org/abstract.cfm?uri=fio-2018-JTu3A.8

A Shahverdi, YM Sua, I Dickson, M Garikapati, YP Huang

Frontiers in Optics, JTu3A. 8 2018

SIGNAL-TO-NOISE RATIO ENHANCEMENT VIA MODE SELECTIVE

In the past decades, the power of light wave technology has revolutionized infrastructure for telecommunications, remote sensing, meteorology, and many others. Similar to the counterpart technologies in radio-frequency, microwave and Terahertz systems, detection of desired signal against noise and interference is essential to optical measurement-based systems and lies at the heart of measurement and signal processing. In reality, optical signal often overlaps with different sources of noise, whether they are from the light source, ambient environment, or the photodetector itself. These may occur either in the same frequency band or even at the same detection time interval. Signal-to-noise ratio (SNR) is a figure of merit that describes the level of the detected signal to the level of the background noise. Standard methods to improve SNR include spectral filtering, time gating, and a combination of the two, called time …

https://scholar.google.com/scholar?cluster=1887257735495857435&hl=en&oi=scholarr

A Shahverdi

STEVENS INSTITUTE OF TECHNOLOGY 2018

Interaction-free All-optical Modulation on Chip

We report the observation of quantum Zeno blockade on chip, where a lightwave is modulated by another in a distinct “interaction-free” manner. For quantum applications, we also verify its operations on single photons.

https://opg.optica.org/abstract.cfm?uri=FiO-2017-JW4A.12

JY Chen, YM Sua, ZT Zhao, M Li, YP Huang

Frontiers in Optics, JW4A. 12 2017

Selective Detection of Picosecond Overlapping Quantum Modes

We demonstrate selective frequency conversion of single photons in overlapping quantum modes of picosecond waveforms, achieving a detection signal-to-noise well exceeding the theoretical limit of the optimal time-frequency filtering.

https://opg.optica.org/abstract.cfm?uri=ls-2017-JW4A.27

A Shahverdi, YM Sua, YP Huang

Laser Science, JW4A. 27 2017

Quantum interference of independently generated telecom-band single photons

We report on high-visibility quantum interference of independently generated telecom O-band (1310 nm) single photons using standard single-mode fibers. The experimental data are shown to agree well with the results of simulations using a comprehensive quantum multimode theory without the need for any fitting parameter.

https://aip.scitation.org/doi/abs/10.1063/1.4903152

M Patel, JB Altepeter, YP Huang, NN Oza, P Kumar

AIP Conference Proceedings 1633 (1), 249-251 2014

Interaction-free All-optical Switches for Quantum Applications

We present a realization of all-optical switching in whispering-gallery-mode microcavities. Operating without the control and probe light beams overlapping in the cavity (in the asymptotic limit), such switches are ideal for use with quantum signals.

https://opg.optica.org/abstract.cfm?uri=fio-2014-FM4B.2

YP Huang, AS Kowligy, YZ Sun, DV Strekalov, P Kumar

Frontiers in Optics, FM4B. 2 2014

Biological source of correlated photon pairs

Photon pairs sources based on nonlinear optical techniques are essential components in modern quantum optical systems. We present here a naturally occurring biological source of photon pairs—Green Fluorescent Protein (GFP)—obtained by a non-degenerate four-wave mixing (FWM).

https://ieeexplore.ieee.org/abstract/document/6989173/

A Thomas, SY Shi, N Corzo, J Altepeter, YP Huang, P Kumar

2014 Conference on Lasers and Electro-Optics (CLEO)-Laser Science to … 2014

High-Performance Single-Photon Sources via Spatial Multiplexing

Single photons sources are desired for many potential quantum information applications. One common method to produce single photons is based on a heralding protocol, which involves generating a pair of photons in an optical nonlinear medium and then detecting one photon in the pair to announce the existence of the other photon of the pair. Compared to other schemes, such a method offers several significant advantages. A major challenge to overcome which is inherent to this method, however, is that the photon pairs are created stochastically in the optical nonlinear medium. Thus, in order to ensure high purity levels for the single photons generated via heralding, sources of this type must be operated at low photon-pair production rates in order to keep the probability for simultaneous creation of multiple photon-pairs to an acceptably low level. A direct result of this restriction is a low heralding rate of single photons. A potential solution for achieving high-rate, high-purity, single-photon generation combines several heralding single-photon sources which are actively multiplexed to act as one source. The overall goal of this project is to develop methods to perform such multiplexing based on the use of a low loss high speed fiber optical switch.

https://apps.dtic.mil/sti/citations/ADA626351

K McCusker, YP Huang, G Kanter, ...

2014

Experimental Demonstration of All-Optical Switching Using the Quantum Zeno Effect

We experimentally demonstrate interaction-free all-optical switching via the quantum Zeno effect. The switch contrast is 35: 1, and the experimental data matches a parameter-free fit. We discuss possible applications and future extensions.

https://opg.optica.org/abstract.cfm?uri=QIM-2013-Th4A.2

KT McCusker, YP Huang, AS Kowligy, P Kumar

Quantum Information and Measurement, Th4A. 2 2013

Mode-selective all-optical switching via quantum frequency conversion

We propose mode-selective all-optical switching by utilizing quantum frequency conversion in a single-mode regime. This can potentially augment existing tools for all-optical information processing in the quantum domain.

https://opg.optica.org/abstract.cfm?uri=cqo-2013-M6.32

A Kowligy, P Kumar, YP Huang

Conference on Coherence and Quantum Optics, M6. 32 2013

All-optical quantum switching

We will present progress in ultrafast all-optical quantum switching. c (3)-based devices can route entangled photons without disturbing their quantum state, whereas c (2)-based devices can, in principle, lead to dissipation-free quantum-optical Fredkin gates.

https://opg.optica.org/abstract.cfm?uri=Photonics-2012-W1C.1

P Kumar, YP Huang

International Conference on Fibre Optics and Photonics, W1C. 1 2012

Ultrafast switching of photonic entanglement

We present our recent development of fiber-optic technology for all-optical switching and routing of entangled photons at high speeds, with minimal loss and added in-band noise, and-most importantly-without disturbing the photons' quantum state.

https://ieeexplore.ieee.org/abstract/document/6358668/

NN Oza, YP Huang, P Kumar

IEEE Photonics Conference 2012, 413-414 2012

Quantum information processing in the telecom waveband

We present recent progress in all-optical routing of entangled single photons at high speeds, with minimal loss and added in-band noise, and-most importantly-without disturbing the photons' quantum state.

https://ieeexplore.ieee.org/abstract/document/6476434/

P Kumar, YP Huang, JB Altepeter, M Patel, NN Oza, MA Hall

OFC/NFOEC, 1-3 2012

Lossless single photon shaping via heralding

Using spontaneous optical parametric down-conversion, we analyze and experimentally demonstrate heralded generation of shaped single photons, whose modes are losslessly tailored via amplitude modulation on the pump field that drives the down-conversion process.

https://opg.optica.org/abstract.cfm?uri=nlo-2011-NMB6

YP Huang, KG Köprülü, GA Barbosa, P Kumar

Nonlinear Optics: Materials, Fundamentals and Applications, NMB6 2011

Omni-directional collective emission of paired photons from atomic vapors

Spontaneous four-wave mixing can generate highly correlated photon pairs from atomic vapors. We show that multi-photon pumping of dipole-forbidden transitions in arecoil-free'geometry can result in ultra-bright pair-emission in the full 4π solid angle with strongly suppressed background Rayleigh scattering. Pair production rates of∼ 10^ 12 per second are predicted, given only moderate optical depths of 10∼ 100, with subnatural bandwidth biphotons obtainable at lower rates. Collective excitation and coherence dynamics are studied numerically, via a nonlinear extension of the optical Bloch equations, for two realistic schemes, based on^ 133Cs and^ 171Yb level structures. Dark-state adiabatic following (EIT) and/or a timescale hierarchy are shown to protect the paired photons from reabsorption.

https://ui.adsabs.harvard.edu/abs/2010APS..DMP.Q6005M/abstract

M Moore, Y Huang

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 55 … 2010

An Ultra-Bright Omnidirectional Atomic-Vapor Photon-Pair Source Based on Doppler-Free Four-Wave-Mixing and Collective Emission

Four-Wave Mixing (FWM) in atomic vapors has become competitive with solid-state down-conversion as a source of entangled photon pairs. FWM schemes rely on collective enhancement to generate strong pair correlation. In general, collective enhancement is only achieved in a very narrow emission solid-angle, restricting the obtainable beam brightness of photon pairs. To substantially increase the pair production rate, we propose a novelbutterfly'level scheme for omnidirectional photon pair generation. With multi-photon Doppler-free pumping, background Rayleigh scattering is dipole-forbidden, and collective emission is permitted in all directions. A pair production rate of 10^ 12 per second should be obtainable with an ensemble of only∼ 10^ 6 atoms. Individual pairs also exhibit near-maximum polarization entanglement over a wide solid-angle. In addition, suppressed Rayleigh scattering significantly reduces …

https://ui.adsabs.harvard.edu/abs/2009APS..DMP.T1092H/abstract

Y Huang, M Moore

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 40 … 2009

Interaction-and Measurement-Free Quantum Zeno Gates for Single-Atom and Single-Photon Qubits

By extending the Elitzur Vaidman concept of interaction-free imaging to the few-atom level, we show that on-demand interaction-and measurement-free quantum logic gates can be realized for both single-atom and single-photon qubits [1]. We present a general theory of quantum Zeno phase gates, and describe physical implementations of several useful quantum gates for universal quantum information processing with individual atomic and photonic qubits in a high-Q ring cavity.[1] YP Huang and MG Moore, Phys. Rev. A 77, 062332 (2008).

https://ui.adsabs.harvard.edu/abs/2009APS..DMP.T1065H/abstract

Y Huang, M Moore

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 40 … 2009

Mixing light and matter waves: Principles and applications

The work of this dissertation is committed to theoretically explore rich physics involving quantum-mechanical mixing of light and matter waves, while specifically seeking applications in the fields of quantum interferometry, quantum information processing, and testing fundamental quantum mechanics. Towards this goal, the present research is guided by two lines. The first line is to study and manipulate collective behaviors of multi-atom systems at quantum-degenerate temperature, where the wave nature of atoms is maximized. Specifically, a variety of phase-coherent mixing processes of two macroscopic matter-waves, in the form of gaseous Bose-Einstein condensate (BEC), are investigated and engineered via (i) tuning atomic collisional interaction and/or inter-wave tunneling rate;(ii) mixing with optical waves of phase-locked lasers. By these means, a series of novel applications are proposed for generating highly …

https://search.proquest.com/openview/7b3de246b14afa2ca4f68dbf2927329f/1?pq-origsite=gscholar&cbl=18750

Y Huang

Michigan State University 2009

Interaction-and measurement-free quantum information processing with single-atom and/or single-photon qubits

Interaction-free measurement (IFM) uses quantum interference to allow a single photon to detect a perfectly absorbing object without the photon interacting with the object directly. In high-efficiency IFM, the Quantum Zeno Effect is employed to increase the success probability from the original 50% to (Na)/N, where N is the number of cycles the photon makes through the device and a 1. In principle IFM protocols allow the hyperfine state of a single atom to become entangled with the polarization of a single photon. To date, attempts to employ this entanglement to create universal atom-atom quantum logic gates, such as CNOT gates, have not succeeded in achieving (Na)/N efficiency. In addition, they also require the detection of ancillary photons. At present, single-photon detection cannot be implemented experimentally with high efficiency. By making several key modications, we have developed a pair of …

https://ui.adsabs.harvard.edu/abs/2007APS..DMP.W5002M/abstract

M Moore, Y Huang

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 38 … 2007

Measuring an unknown phase with quantum-limited precision using nonlinear beamsplitters

High precision phase measurement is currently a central goal of quantum interferometry. In general, the precision is described by the phase estimation uncertainty δθ, which is characterized by two scaling behaviors, shot-noise limited with δθ∼ 1/√ N and Heisenberg limited with δθ∼ 1/N (N the total particle number). According to Bayesian analysis, Heisenberg limited preciosion for θ= 0 can be achieved in a Mach-Zehnder interferometer with (| N-1, N+ 1>+| N+ 1, N-1>)/√ 2 as input state based and a single measurement or| N, N> input based on multiple measurements. As θ deviates from zero, both schemes degrade rapidly to worse than shot-noise-limited precision. In contrast, a Quantum Fourier Transform (QFT) based interferometer can measure an arbitrary θ at Heisenberg limited precision, but requires a quantum computer. To extend the range of precisely measurable θ without a quantum computer, we …

https://ui.adsabs.harvard.edu/abs/2007APS..DMP.W5001H/abstract

Y Huang, M Moore

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts 38 … 2007

Gaussian number-squeezed states for sub-shot-noise interferometery in double-well Bose-Einstein condensates

This paper has been withdrawn. It is based on numerical results limited by computing resources to N= 3000 atoms. Using a newly understood geometric method we find that the observed scaling with N saturates at around N= 7000 or even higher. In light of this new finding we withdraw the paper and will submit a revised manuscript reflecting our new understanding.

https://ui.adsabs.harvard.edu/abs/2007arXiv0705.3376H/abstract

YP Huang, MG Moore

arXiv e-prints, arXiv: 0705.3376 2007

Creation, detection and decoherence of Schrodinger cat states in Bose-Einstein condensates

We study the possibility to create many-particle Schr\"odinger cat-like states by using a Feshbach resonance to reverse the sign of the scattering length of a Bose-Einstein condensate trapped in a double-well potential. To address the issue of experimental verification of coherence in the cat-like state, we study the revival of the initial condensate state in the presence of environmentally-induced decoherence. As a source of decoherence, we consider the interaction between the atoms and the electromagnetic vacuum, due to the polarization induced by an incident laser field. We find that the resulting decoherence is directly related to the rate at which spontaneously scattered photons carry away sufficient information to distinguish between the two atom-distributions which make-up the cat state. We show that for a 'perfect' cat-state, a single scattered photon will bring about a collapse of the superposition, while a less-than-perfect cat-like state can survive multiple scatterings before collapse occurs. In addition, we study the dephasing effect of atom-atom collisions on the cat-like states.

https://arxiv.org/abs/cond-mat/0508659

YP Huang, MG Moore

arXiv preprint cond-mat/0508659 2005