© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Physical Review A

Multichannel nonreciprocal amplifications using cesium vapor

Yaodong Hu, Guo-Qiang Zhang

Published May 31, 2023• 4 citations

Abstract

Multichannel synchronous amplifications are an inevitable key problem in quantum communication process, which can broaden the bandwidth of transmitted signals and establish correlation among different optical channels. Here we study a nonreciprocal system with four concurrent amplification channels using hot cesium atoms, both theoretically and experimentally. For the forward probe field, the double--electromagnetically induced transparency structure is formed and the phase-matching condition of the multiwave mixing process is satisfied, which are both destroyed when the probe field is reversed. In addition, the four-channel nonreciprocal amplifications are formed in the Zeeman sublevels of the system with special selection of light field polarization, which will also dramatically enhance the signal-to-noise ratio by suppressing the spontaneous emission noise of the system. In our experiment, the quadruple nonreciprocal amplifications are achieved with the maximum forward gain reaching 30 dB and the reverse suppression reaching--23 dB. The gain adjustability allows the construction of a gain-loss balanced system, providing a scheme for an atomic system to engineer a parity-time-symmetric (or -antisymmetric) structure.

DOI: 10.1103/physreva.107.053716

Related papers

Ultra-strong nonreciprocal amplification with hot atoms

Hang Zhou Yang, Shicheng Zhang, Yueping Niu +1 more

Optical nonreciprocity plays an important role in optical communication and signal processing. Here, we propose and demonstrate a magnetic-free optical nonreciprocal amplification based on a far-detuned four-wave mixing process in hot atoms. The absorption of the probe field can be significantly reduced by the large detuning. In our experiment, with just one pump field, an ultra-strong forward gain of 45 dB is achieved while the backward one keeps a near unit transmission. The experimental realization of ultra-strong nonreciprocal amplification may have applications for the generation of strong nonreciprocal quantum correlations.

Optics Communications•Mar 16, 2022•7 citations

Optical reciprocity-nonreciprocity-amplification conversion based on degenerate four-wave mixing

Dan Song, Xin Li, Haitao Zhou +5 more

Optical nonreciprocity plays an important role in optical communication and quantum networks. In this research, we propose and demonstrate a conversion scheme of magnetic-free dual-channel optical reciprocal amplification (RA) and nonreciprocal amplification (NRA) based on the multiple degenerate four-wave mixing (FWM) process in hot atoms. In our experiment, the dual-channel NRA works with the action of a single pump field based on the establishment of FWM in the same direction and breaking in the opposite direction. Based on stable ground-state Zeeman coherence, by introducing a counter-propagating pump field again, NRA can be changed to RA in the opposite direction of the two original amplified conjugate signals. Moreover, the frequencies of RA signals are very dependent on those of co-propagating pump fields. The experimental realization of NRA-RA conversion may have applications for multichannel angular momentum spatial multiplexing and quantum gate manipulation.

Journal of the Optical Society of America B•Mar 7, 2024•5 citations

Nonreciprocal Amplification with Four-Level Hot Atoms

Gongwei Lin, Shicheng Zhang, Yiqi Hu +3 more

Optical nonreciprocity is of paramount importance to optical signal processing and one-way optical communication. Here, we theoretically and experimentally demonstrate nonreciprocal amplification based on four-level hot atoms by exploiting atomic Doppler shifts. Our approach is simple and easy to implement. In fair agreement with our theoretical modeling, forward power amplification of 26 dB and backward isolation of 30 dB are observed. Our results will open up a new avenue towards realistic devices based on nonreciprocal amplification.

Physical Review Letters•Jul 18, 2019•111 citations

Narrowband nonreciprocal transmission in a Doppler-broadened multilevel atomic system

Ying-Xue Zhang, Hui-Min Zhao, Yan-Kui Bai

We theoretically investigate narrowband nonreciprocal transmission in a Doppler-broadened five-level M-type atomic medium. After Doppler averaging, the M-type system retains a narrow near-resonant electromagnetically induced transparency window that is narrower than that of a standard three-level $Λ$ system. This spectral narrowing is associated with the decreasing separation between the two inner dressed states as atomic velocity increases. The transparency window exhibits pronounced direction-dependent transmission, with high forward transmission and strong suppression in the reverse direction. The transparency linewidth and forward-backward probe transmission can be controlled via two independent driving fields, while the central transparency frequency is kept essentially unchanged. The resulting narrowband nonreciprocity supports high forward transmission together with strong suppression in the reverse direction, which is suitable for frequency-selective optical filtering and nonreciprocal optical transmission in thermal atomic media. Our scheme with these specific features is geared towards enabling compact vapor-cell-based nonreciprocal devices for quantum network applications.

quant-pharXiv:2610.27792•Oct 21, 2026•0 citations

Nonreciprocity in Cold Atoms Based on Electromagnetically Induced Transparency

J. Li, Yunfei Wang, Peisheng Huang +5 more

Nonreciprocal quantum devices with low loss are indispensable in quantum information processing but challenging to be realized. Here we report an experiment to realize the nonreciprocal phase shift larger than $\ensuremath{\pi}$ with low loss in a cavity-free and magnetic-free cold atomic ensemble based on electromagnetically induced transparency. Furthermore, a four-port all-optical circulator is demonstrated with an average isolation ratio of 22.25 dB and transmission of 0.94 for each channel. At its optimal working point, the circulator's total isolation ratio reaches 63.47 dB, transmission reaches 0.86, and fidelity at about 0.99. Our work can advance further investigation of nonreciprocity with cold atoms in quantum information processing applications.

Physical Review Applied•Jul 13, 2023•7 citations

Optical nonreciprocity and nonreciprocal photonic devices with directional four-wave mixing effect

Tao Shui, Wen‐Xing Yang, Mu-Tian Cheng +1 more

A scheme for magnetic-free optical nonreciprocity in an ensemble of four-level cold atoms is proposed by exploiting the directional four-wave mixing effect. Using experimentally achievable parameters, the nonreciprocal optical responses of the system can be observed and the conversion on nonreciprocal transmission and nonreciprocal phase shift can be implemented. These nonreciprocal phenomena originate from the directional phase matching, which breaks the time-reversal symmetry and dynamic reciprocity of the cold atomic system. Moreover, by embedding the cold atoms into a Mach-Zehnder interferometer and choosing proper parameters, a two-port optical isolator with an isolation ratio of 79.70 dB and an insertion loss of 0.35 dB and a four-port optical circulator with a fidelity of 0.9985 and a photon survival probability of 0.9278 can be realized, which shows the high performance of isolation and circulation. The proposal may enable a new class of optically controllable cavity-free nonreciprocal devices in optical signal processing at the low light level.

Optics Express•Feb 4, 2022•28 citations

Multichannel synchronous amplifications are an inevitable key problem in quantum communication process, which can broaden the bandwidth of transmitted signals and establish correlation among different optical channels. Here we study a nonreciprocal system with four concurrent amplification channels using hot cesium atoms, both theoretically and experimentally. For the forward probe field, the double--electromagnetically induced transparency structure is formed and the phase-matching condition of the multiwave mixing process is satisfied, which are both destroyed when the probe field is reversed. In addition, the four-channel nonreciprocal amplifications are formed in the Zeeman sublevels of the system with special selection of light field polarization, which will also dramatically enhance the signal-to-noise ratio by suppressing the spontaneous emission noise of the system. In our experiment, the quadruple nonreciprocal amplifications are achieved with the maximum forward gain reaching 30 dB and the reverse suppression reaching--23 dB. The gain adjustability allows the construction of a gain-loss balanced system, providing a scheme for an atomic system to engineer a parity-time-symmetric (or -antisymmetric) structure.

Optical nonreciprocity plays an important role in optical communication and signal processing. Here, we propose and demonstrate a magnetic-free optical nonreciprocal amplification based on a far-detuned four-wave mixing process in hot atoms. The absorption of the probe field can be significantly reduced by the large detuning. In our experiment, with just one pump field, an ultra-strong forward gain of 45 dB is achieved while the backward one keeps a near unit transmission. The experimental realization of ultra-strong nonreciprocal amplification may have applications for the generation of strong nonreciprocal quantum correlations.

Optical nonreciprocity plays an important role in optical communication and quantum networks. In this research, we propose and demonstrate a conversion scheme of magnetic-free dual-channel optical reciprocal amplification (RA) and nonreciprocal amplification (NRA) based on the multiple degenerate four-wave mixing (FWM) process in hot atoms. In our experiment, the dual-channel NRA works with the action of a single pump field based on the establishment of FWM in the same direction and breaking in the opposite direction. Based on stable ground-state Zeeman coherence, by introducing a counter-propagating pump field again, NRA can be changed to RA in the opposite direction of the two original amplified conjugate signals. Moreover, the frequencies of RA signals are very dependent on those of co-propagating pump fields. The experimental realization of NRA-RA conversion may have applications for multichannel angular momentum spatial multiplexing and quantum gate manipulation.

Optical nonreciprocity is of paramount importance to optical signal processing and one-way optical communication. Here, we theoretically and experimentally demonstrate nonreciprocal amplification based on four-level hot atoms by exploiting atomic Doppler shifts. Our approach is simple and easy to implement. In fair agreement with our theoretical modeling, forward power amplification of 26 dB and backward isolation of 30 dB are observed. Our results will open up a new avenue towards realistic devices based on nonreciprocal amplification.

We theoretically investigate narrowband nonreciprocal transmission in a Doppler-broadened five-level M-type atomic medium. After Doppler averaging, the M-type system retains a narrow near-resonant electromagnetically induced transparency window that is narrower than that of a standard three-level

Λ

system. This spectral narrowing is associated with the decreasing separation between the two inner dressed states as atomic velocity increases. The transparency window exhibits pronounced direction-dependent transmission, with high forward transmission and strong suppression in the reverse direction. The transparency linewidth and forward-backward probe transmission can be controlled via two independent driving fields, while the central transparency frequency is kept essentially unchanged. The resulting narrowband nonreciprocity supports high forward transmission together with strong suppression in the reverse direction, which is suitable for frequency-selective optical filtering and nonreciprocal optical transmission in thermal atomic media. Our scheme with these specific features is geared towards enabling compact vapor-cell-based nonreciprocal devices for quantum network applications.

Nonreciprocal quantum devices with low loss are indispensable in quantum information processing but challenging to be realized. Here we report an experiment to realize the nonreciprocal phase shift larger than $\ensuremath{\pi}$ with low loss in a cavity-free and magnetic-free cold atomic ensemble based on electromagnetically induced transparency. Furthermore, a four-port all-optical circulator is demonstrated with an average isolation ratio of 22.25 dB and transmission of 0.94 for each channel. At its optimal working point, the circulator's total isolation ratio reaches 63.47 dB, transmission reaches 0.86, and fidelity at about 0.99. Our work can advance further investigation of nonreciprocity with cold atoms in quantum information processing applications.

A scheme for magnetic-free optical nonreciprocity in an ensemble of four-level cold atoms is proposed by exploiting the directional four-wave mixing effect. Using experimentally achievable parameters, the nonreciprocal optical responses of the system can be observed and the conversion on nonreciprocal transmission and nonreciprocal phase shift can be implemented. These nonreciprocal phenomena originate from the directional phase matching, which breaks the time-reversal symmetry and dynamic reciprocity of the cold atomic system. Moreover, by embedding the cold atoms into a Mach-Zehnder interferometer and choosing proper parameters, a two-port optical isolator with an isolation ratio of 79.70 dB and an insertion loss of 0.35 dB and a four-port optical circulator with a fidelity of 0.9985 and a photon survival probability of 0.9278 can be realized, which shows the high performance of isolation and circulation. The proposal may enable a new class of optically controllable cavity-free nonreciprocal devices in optical signal processing at the low light level.