Nonreciprocal Transmission of Microwave Acoustic Waves in Nonlinear Parity-Time Symmetric Resonators

Magnetless Reflective Gyrotropic Spatial Isolator Metasurface

We present the concept of a magnetless Reflective Gyrotropic Spatial Isolator (RGSI) metasurface. This is a birefringent metasurface that reflects vertically polarized incident waves into a horizontally polarized waves, and absorbs horizontally polarized incident waves, hence providing isolation between the two orthogonal polarization. We first synthesize the metasurface using surface susceptibility-based Generalized Sheet Transition Conditions~(GSTCs). We then propose a mirror-backed metaparticle implementation of this metasurface, where transistor-loaded resonators provide the desired magnet…

Reservoir computing using a spin-wave delay line active ring resonator

The authors demonstrate the use of a propagating spin waves for implementing a reservoir computing architecture. The proposed concept utilises an active ring resonator comprising a magnetic thin film delay line integrated into a feedback loop. These systems exhibit strong nonlinearity and delayed response behaviour, two important properties required for an effective reservoir computing implementation. In a simple design, we exploit the nonlinear damping of spin waves at different feedback gains to inject input data into the active ring resonator and use a microwave diode to read out the amplit…

横向超导二极管无需宇称和时间反演破坏

Transverse superconducting diode without parity and time-reversal violation

通过偏置电流调控平面各向异性超导体实现无需破坏P或T对称性的横向超导二极管效应，提出电流门控正交超导晶体管并展示其在可调超流电流控制器和半波整流器中的应用。

Mirror symmetric on-chip frequency circulation of light

Integrated circulators and isolators are important for developing on-chip optical technologies, such as laser cavities, communication systems, and quantum information processors. These devices appear to inherently require mirror symmetry breaking to separate backwards from forwards propagation, so existing implementations rely upon magnetic materials, or interactions driven by propagating waves. In contrast to previous work, we demonstrate a mirror symmetric nonreciprocal device. Our device comprises three coupled photonic resonators implemented in thin-film lithium niobate. Applying radio fre…

All-optical nonreciprocity due to valley polarization in transition metal dichalcogenides

Nonreciprocity and nonreciprocal optical devices play a vital role in modern photonic technologies by enforcing one-way propagation of light. Most nonreciprocal devices today are made from a special class of low-loss ferrites that exhibit a magneto-optical response in the presence of an external static magnetic field. While breaking transmission symmetry, ferrites fail to satisfy the need for miniaturization of photonic circuitry due to weak character of nonreciprocal responses at optical wavelengths and are not easy to integrate into on-chip photonic systems. These challenges led to the emerg…

实空间成像揭示机械谐振器中对称性选择的非线性能量路由

Real-space imaging reveals symmetry-selected nonlinear energy routing in a mechanical resonator

通过锁相多谐波频闪干涉术直接成像微机电谐振器中的非线性模态能量路由，发现谐波由不同空间本征模态携带，且镜像奇偶性决定非线性模态相互作用的选律。

Parity-time symmetry in wavelength space with spatial singularity

Implementation of a parity-time (PT) symmetric microwave photonic system in the optical wavelength space with spatial singularity is proposed. In the proposed PT-symmetric microwave photonic system, the gain and loss modes are confined in a single spatial resonator, which is different from a conventional PT-symmetric system in which the two modes are localized in two physically separated resonators to form one-dimensional spatial potential symmetry as required by the simplest one-dimensional parity transformation. We show that PT-symmetry can be implemented between subspaces in non-spatial par…

Observation of parity-time symmetry in electrically pumped FP laser

Parity-time (PT) symmetry is a new method to get single mode operation in lasers, mostly, micro-ring lasers. In this study, we propose and experimentally demonstrate an electrically pumped PT symmetric Fabry-Perot (FP) laser which can work with a mode selection. The proposed laser could achieve the PT symmetric condition by an electrical manipulation of the interplay between gain and loss in two FP resonators. The single mode lasing is demonstrated at 1574.6nm with a 20.81dB sidemode suppression ratio.