Modern information networks are built on hybrid systems working at disparate optical wavelengths. Coherent interconnects for converting photons between different wavelengths are highly desired. Although coherent interconnects have conventionally been realized with nonlinear optical effects, those systems require demanding experimental conditions, such as phase matching and/or cavity enhancement, which not only bring difficulties in experimental implementation but also set a narrow tuning bandwidth (typically in the MHz to GHz range as determined by the cavity linewidth). Here, we propose and experimentally demonstrate coherent information transfer between two orthogonally propagating light beams of disparate wavelengths in a fiber-based optomechanical system, which does not require phase matching or cavity enhancement of the pump beam. The coherent process is demonstrated by interference phenomena similar to optomechanically induced transparency and absorption. Our scheme not only significantly simplifies the experimental implementation of coherent wavelength conversion but also extends the tuning bandwidth to that of an optical fiber (tens of THz), which will enable a broad range of coherent-optics-based applications, such as optical sensing, spectroscopy, and communication.

基于减小模组应力，系统的研究了工艺、材料、设计对黑态均一性的影响，确定出可满足70% 面扫的方案。实验结果表明：1）模组设计上采用减薄至0.4 mm的液晶屏搭配1.3 mm厚度的盖板；2）材料选择使用上下材质一致的偏光片，液态光学贴合胶，低温各向异性导电胶；3）对盒工艺降低机械臂运行速度，可将车载液晶显示器模组的面扫黑态均匀性提升到70%。

We theoretically and experimentally demonstrate that magnetic plasmonic gradient metasurfaces (GMSs) can convert a spatially propagating wave to a one-way edge state or vice versa with high efficiency. Consisting of an array of ferrite rods with a rotation gradient introduced to the rod dimers in the unit cell, GMSs can covert an incident wave beam to a one-way edge state with efficiency over 77%, and almost fully radiate into free space from the one-way edge state. The phenomenon arises from the unidirectional coupling of the spatial electromagnetic wave with magnetic plasmonic GMSs, which is evidenced from the photonic band diagrams of the edge state. The one-way edge state can radiate to or be excited from air with different angles by either engineering the gradient of the GMSs or tuning the bias magnetic field. By designing magnetic plasmonic GMSs with more exquisite configurations, we can expect many more nonreciprocal properties, adding additional freedom in manipulating electromagnetic waves.

The recent realizations of a topological valley phase in a photonic crystal, an analog of gapped valleytronic materials in an electronic system, are limited to the valley Chern number of one. In this paper, we present a type of valley phase that can have a large valley Chern number of two or three. The valley phase transitions between the different valley Chern numbers (from one to three) are realized by changing the configuration of the unit cell. We demonstrate that these topological phases can guide the wave propagation robustly along a sharply bent domain wall. We believe our results are promising for the exploration of new topological phenomena in photonic systems.