arXiv subjects

Yan-Lei Zhang

Publications and source records attributed to Yan-Lei Zhang.

At least 37 records · Page 2Linked to original sources

arXiv2022

High-frequency traveling-wave phononic cavity with sub-micron wavelength

Thin-film gallium nitride (GaN) as a proven piezoelectric material is a promising platform for the phononic integrated circuits, which hold great potential for scalable information processing processors. Here, an unsuspended traveling phononic resonator based on high-acoustic-index-contrast mechanism is realized in GaN-on-Sapphire with a frequency up to 5 GHz, which matches the typical superconducting qubit frequency. A sixfold increment in quality factor was found when temperature decreases from room temperature ($Q=5000$) to $7\,\mathrm{K}$ ($Q=30000$) and thus a frequency-quality factor product of $1.5\times10^{14}$ is obtained. Higher quality factors are available when the fabrication process is further optimized. Our system shows great potential in hybrid quantum devices via circuit quantum acoustodynamics.

physics.app-ph↗

arXiv2022

Adiabatic conversion between gigahertz quasi-Rayleigh and quasi-Love modes for phononic integrated circuits

Unsuspended phononic integrated circuits have been proposed for on-chip acoustic information processing. Limited by the operation mechanism of a conventional interdigital transducer, the excitation of the quasi-Love mode in GaN-on-Sapphire is inefficient and thus a high-efficiency Rayleigh-to-Love mode converter is of great significance for future integrated phononic devices. Here, we propose a high-efficiency and robust phononic mode converter based on an adiabatic conversion mechanism. Utilizing the anisotropic elastic property of the substrate, the adiabatic mode converter is realized by a simple tapered phononic waveguide. A conversion efficiency exceeds $98\%$ with a $3\,\mathrm{dB}$ bandwidth of $1.7\,\mathrm{GHz}$ can be realized for phononic waveguides working at GHz frequency band, and excellent tolerance to the fabrication errors is also numerically validated. The device that we proposed can be useful in both classical and quantum phononic information processing, and the adiabatic mechanism could be generalized to other phononic device designs.

physics.app-ph↗

arXiv2022

Non-reciprocal frequency conversion and mode routing in a microresonator

The transportation of photons and phonons typically obeys the principle of reciprocity. Breaking reciprocity of these bosonic excitations will enable the corresponding non-reciprocal devices, such as isolators and circulators. Here, we use two optical modes and two mechanical modes in a microresonator to form a four-mode plaquette via radiation pressure force. The phase-controlled non-reciprocal routing between any two modes with completely different frequencies is demonstrated, including the routing of phonon to phonon (MHz to MHz), photon to phonon (THz to MHz), and especially photon to photon with frequency difference of around 80 THz for the first time. In addition, one more mechanical mode is introduced to this plaquette to realize a phononic circulator in such single microresonator. The non-reciprocity is derived from interference between multi-mode transfer processes involving optomechanical interactions in an optomechanical resonator. It not only demonstrates the non-reciprocal routing of photons and phonons in a single resonator but also realizes the non-reciprocal frequency conversion for photons and circulation for phonons, laying a foundation for studying directional routing and thermal management in an optomechanical hybrid network.

physics.optics↗

arXiv2021

Classical-to-quantum transition in multimode nonlinear systems with strong photon-photon coupling

With advanced micro- and nano-photonic structures, the vacuum photon-photon coupling rate is anticipated to approach the intrinsic loss rate and lead to unconventional quantum effects. Here, we investigate the classical-to-quantum transition of such photonic nonlinear systems using the quantum cluster-expansion method, which addresses the computational challenge in tracking large photon number states of the fundamental and harmonic optical fields involved in the second harmonic generation process. Compared to the mean-field approximation used in weak coupling limit, the quantum cluster-expansion method solves multimode dynamics efficiently and reveals the quantum behaviors of optical parametric oscillations around the threshold. This work presents a universal tool to study quantum dynamics of multimode systems and explore the nonlinear photonic devices for continuous-variable quantum information processing.

quant-ph↗

arXiv2021

Single-sideband microwave-to-optical conversion in high-Q ferrimagnetic microspheres

Coherent conversion of microwave and optical photons can significantly expand the ability to control the information processing and communication systems. Here, we experimentally demonstrate the microwave-to-optical frequency conversion in a magneto-optical whispering gallery mode microcavity. By applying a magnetic field parallel to the microsphere equator, the intra-cavity optical field will be modulated when the magnon is excited by the microwave drive, leading to microwave-to-optical conversion via the magnetic Stokes and anti-Stokes scattering processes. The observed single sideband conversion phenomenon indicates a non-trivial optical photon-magnon interaction mechanism, which is derived from the magnon induced both the frequency shift and modulated coupling rate of optical modes. In addition, we demonstrate the single-sideband frequency conversion with an ultrawide tuning range up to 2.5GHz, showing its great potential in microwave-to-optical conversion.

physics.optics↗

arXiv2020

Nonreciprocal Optomechanical Entanglement against Backscattering Losses

We propose how to achieve nonreciprocal quantum entanglement of light and motion and reveal its counterintuitive robustness against random losses. We find that by splitting the counterpropagating lights of a spinning resonator via the Sagnac effect, photons and phonons can be entangled strongly in a chosen direction but fully uncorrelated in the other. This makes it possible both to realize quantum nonreciprocity even in the absence of any classical nonreciprocity and also to achieve significant entanglement revival against backscattering losses in practical devices. Our work provides a way to protect and engineer quantum resources by utilizing diverse nonreciprocal devices, for building noise-tolerant quantum processors, realizing chiral networks, and backaction-immune quantum sensors.

quant-ph↗

arXiv2020

Unidirectional transmission of single photons under non-ideal chiral photon-atom interactions

Single-photon transport in non-ideal chiral photon-atom interaction structures generally contains information backflow and thus limits the capabilities to transfer information between distant emitters in cascaded quantum networks. Here, in the non-ideal chiral case, a V -type atom coupled to a waveguide is proposed to realize completely unidirectional transmission of the single photons in a superposition state of different frequencies. A microwave field is introduced to drive the two excited states of the atom and results in photon conversion between two transitions. By adjusting the Rabi frequency and the phase of the external driving field, the transport behaviors of incident photons with specific frequencies can be optimized to complete transmission or reflection. Based on the constructive interferences between photons from different traveling paths, the transmission probabilities of the specific-frequency photons could be enhanced. Due to photon conversions with compensating the dissipations and ensuring the complete destructive interference, the ideal unidirectional transmission contrast can be maintained to 1, even when the atom has dissipations into the non-waveguide modes.

physics.optics↗

arXiv2020

Noiseless photonic non-reciprocity via optically-induced magnetization

The realization of optical non-reciprocity is crucial for many device applications, and also of fundamental importance for manipulating and protecting the photons with desired time-reversal symmetry. Recently, various new mechanisms of magnetic-free non-reciprocity have been proposed and implemented, avoiding the limitation of the strong magnetic field imposed by the Faraday effect. However, due to the difficulties in suppressing the drive and its induced noises, these devices exhibit limited isolation performances and leave the quantum noise properties rarely studied. Here, we demonstrate a new approach of magnetic-free non-reciprocity by optically induced magnetization in an atom ensemble. Excellent isolation of signal (highest isolation ratio is 51.4 dB) is observed over a power dynamic range of 7 orders of magnitude, with the noiseless property verified by quantum statistics measurement. The approach is applicable to other atoms and atom-like emitters in solids, paving the way for future studies of integrated photonic non-reciprocal devices, unidirectional quantum storage and state transfer, as well as topological photonics technologies.

physics.optics↗

arXiv2019

Enhanced optomechanical entanglement and cooling via dissipation engineering

We propose an optomechanical dissipation engineering scheme by introducing an ancillary mechanical mode with a large decay rate to control the density of states of the optical mode. The effective linewidth of the optical mode can be reduced or broadened, manifesting the dissipation engineering. To prove the ability of our scheme in improving the performances of the optomechanical system, we studied optomechanical entanglement and phonon cooling. It is demonstrated that the optomechanical entanglement overwhelmed by thermal phonon excitations could be restored via dissipation engineering. For the phonon cooling, an order of magnitude improvement could be achieved. Our scheme can be generalized to other systems with multiple bosonic modes, which is experimentally feasible with advances in materials and nanofabrication, including optical Fabry-Perot cavities, superconducting circuits, and nanobeam photonic crystals.

quant-ph↗

arXiv2019

Photon-photon quantum phase gate in a photonic molecule with $χ^{(2)}$ nonlinearity

The construction of photon-photon quantum phase gate based on photonic nonlinearity has long been a fundamental issue, which is vital for deterministic and scalable photonic quantum information processing. It requires not only strong nonlinear interaction at the single-photon level, but also suppressed phase noise and spectral entanglement for high gate fidelity. In this paper, we propose that high-quality factor microcavity with strong $χ^{(2)}$ nonlinearity can be quantized to anharmonic energy levels and be effectively treated as an artificial atom. Such artificial atom has a size much larger than the photon wavelength, which enables passive and active ultra-strong coupling to traveling photons. High-fidelity quantum control-phase gate is realized by mediating the phase between photons with an intermediate artificial atom in a photonic molecule structure. The scheme avoids the two-photon emission and thus eliminates the spectral entanglement and quantum phase noises. Experimental realization of the artificial atom can be envisioned on the integrated photonic chip and holds great potential for single-emitter-free, room-temperature quantum information processing.

quant-ph↗

arXiv2019

Synthetic gauge field in a single optomechanical resonator

Synthetic gauge fields have recently emerged, arising in the context of quantum simulations, topological matter, and the protected transportation of excitations against defects. For example, an ultracold atom experiences a light-induced effective magnetic field when tunnelling in an optical lattice, and offering a platform to simulate the quantum Hall effect and topological insulators. Similarly, the magnetic field associated with photon transport between sites has been demonstrated in a coupled resonator array. Here, we report the first experimental demonstration of a synthetic gauge field in the virtual dimension of bosonic modes in a single optomechanical resonator. By employing degenerate clockwise (CW) and counter-clockwise (CCW) optical modes and a mechanical mode, a controllable synthetic gauge field is realized by tuning the phase of the driving lasers. The non-reciprocal conversion between the three modes is realized for different synthetic magnetic fluxes. As a proof-of-principle demonstration, we also show the dynamics of the system under a fast-varying synthetic gauge field. Our demonstration not only provides a versatile and controllable platform for studying synthetic gauge fields in high dimensions but also enables an exploration of ultra-fast gauge field tuning with a large dynamic range, which is restricted for a magnetic field.

physics.optics↗

arXiv2018

Quantum states preparation of an atomic ensemble via cavity-assisted homodyne measurement

The quantum spin states of atomic ensemble are of special interesting for both fundamental studies and precision measurement applications. Here, we propose a scheme to prepare collective quantum states of an atomic ensemble placed in an optical cavity via homodyne measurement of probing light field. The effective interactions of atoms mediated by photons are enhanced by the optical cavity, and the output probe light could also be entangled with the collective spin states. By selectively measuring the quadrature of output light, we can prepare various quantum states, including superposition states of Dicke states and Dicke squeezed states. It is also demonstrated that the fidelity of prepared quantum state can be enhanced by repetitive homodyne detection and using longer probe laser pulses. Our scheme is feasible for experimental realization with current technologies, which may be used in future study of quantum mechanics and quantum metrology.

quant-ph↗

arXiv2018

Doubly-resonant-cavity electromagnetically induced transparency

We present an experimental study on the cavity-atom ensemble system, and realize the doubly-resonant cavity enhanced electromagnetically induced transparency, where both the probe and control lasers are resonant with a Fabry-Perot cavity. We demonstrate the precise frequency manipulating of the hybrid optical-atomic resonances, through either temperature or cavity length tuning. In such a system, the control power can be greatly enhanced due to the cavity, and all-optical switching is achieved with a much lower control laser power compared to previous studies. A new theoretical model is developed to describe the effective three-wave mixing process between spin-wave and optical modes. Interesting non-Hermitian physics are predicted theoretically and demonstrated experimentally. Such a doubly-resonant cavity-atom ensemble system without a specially designed cavity can be used for future applications, such as optical signal storage and microwave-to-optical frequency conversion.

physics.optics↗

arXiv2017

Reconfigurable optomechanical circulator and directional amplifier

Non-reciprocal devices, which allow the non-reciprocal signal routing, serve as the fundamental elements in photonic and microwave circuits and are crucial in both classical and quantum information processing. The radiation-pressure-induced coupling between light and mechanical motion in traveling wave resonators has been exploited to break the Lorentz reciprocity, realizing non-reciprocal devices without magnetic materials. Here, we experimentally demonstrate a reconfigurable nonreciprocal device with alternative functions of either a circulator or a directional amplifier via the optomechanically induced coherent photon-phonon conversion or gain. The demonstrated device exhibits considerable flexibility and offers exciting opportunities for combining reconfigurability, non-reciprocity and active properties in single photonic structures, which can also be generalized to microwave as well as acoustic circuits.

physics.optics↗

arXiv2017

Phase-Controlled Phonon Laser

A phase-controlled ultralow-threshold phonon laser is proposed by using tunable optical amplifiers in coupled-cavity-optomechanical system. Giant enhancement of coherent photon-phonon interactions is achieved by engineering the strengths and phases of external parametric driving. This in turn enables single-photon optomechanics and low-power phonon lasing, opening up novel prospects for applications, e.g. quantum phononics and ultrasensitive motion detection.

quant-ph↗

arXiv2017

Optomechanical devices based on traveling-wave microresonators

We theoretically study the unique applications of optomechanics based on traveling-wave microresonators, where the optomechanical coupling of degenerate modes can be enhanced selectively by optically pumping in different directions. We show that the unique features of degenerate optical modes can be applied to the entangled photon generation of clockwise and counter-clockwise optical modes, and the nonclassicality of entangled photon pair is discussed. The coherent coupling between the clockwise and counter-clockwise optical mods and two acoustic modes is also studied, in which the relative phase of the optomechanical couplings plays a key role in the optical non-reciprocity. The parity-time symmetry of acoustic modes can be observed in the slightly deformed microresonator with the interaction of forward and backward stimulated Brillouin Scattering in the triple-resonance system. In addition, the degenerate modes are in the decoherence-free subspace, which is robust against environmental noises. Based on parameters realized in recent experiments, these optomechanical devices should be readily achievable.

quant-ph↗

arXiv2015

Long-distance synchronization of unidirectionally cascaded optomechanical systems

Synchronization is of great scientific interest due to the abundant applications in a wide range of systems. We propose a scheme to achieve the controllable long-distance synchronization of two dissimilar optomechanical systems, which are unidirectionally coupled through a fiber with light. Synchronization, unsynchronization, and the dependence of the synchronization on driving laser strength and intrinsic frequency mismatch are studied based on the numerical simulation. Taking the fiber attenuation into account, it's shown that two mechanical resonators can be synchronized over a distance of tens of kilometers. In addition, we also analyze the unidirectional synchronization of three optomechanical systems, demonstrating the scalability of our scheme.

physics.optics↗

arXiv2015

Phonon induced spin squeezing based on geometric phase

A scheme to achieve spin squeezing using a geometric phase induced by a single mechanical mode is proposed. The analytical and numerical results show that the ultimate degree of spin squeezing depends on the parameter $\frac{n_{th}+1/2}{Q\sqrt{N}}$, which is the ratio between the thermal excitation, the quality factor and square root of ensemble size. The undesired coupling between the spin ensemble and the bath can be efficiently suppressed by Bang-Bang control pulses. With high quality factor, the ultimate limit of the ideal one-axis twisting spin squeezing can be obtained for an NV ensemble in diamond.

quant-ph↗