This paper experimentally demonstrates a distributed photonics-based W-band integrated sensing and communication (ISAC) system, in which radar sensing can aid the communication links in alignment and data rate estimation. As a proof-of-concept, the ISAC system locates the users, guides the alignment, and sets a communication link with the estimated highest data rate. A peak net data rate of 68.6 Gbit/s and a target sensing with a less-than-1-cm error and a sub-2-cm resolution have been tested over a 10-km fiber and a 1.15-m free space transmission in the photonics-based W-band ISAC system. The achievable net data rates of the users at different locations estimated by sensing are experimentally verified.

与常规的自发拉曼散射相比，受激拉曼散射 (SRS) 经常使用两束光场 (泵浦光和Stokes光)，这为偏振操控SRS过程提供了一个额外的自由度。为此，开展了泵浦光分别为圆偏振和线偏振的SRS对比研究。首先，基于非线性耦合波方程，从理论上分别推导了泵浦光为圆偏振和线偏振时 (Stokes光始终保持线偏振) SRS信号强度表达式。随后，以具有球对称的甲烷分子为例，实验测量了上述两种偏振光泵浦下甲烷分子υ₁和υ₃振动模在2800~3100 cm^-1的SRS光谱。实验结果与理论分析一致表明：SRS的信号强度不仅与泵浦光的偏振态有关，还与待测分子振动模式的对称性紧密相关。本研究结果为SRS的偏振应用提供了有益启示。

Achieving spatiotemporal control of light at high speeds presents immense possibilities for various applications in communication, computation, metrology, and sensing. The integration of subwavelength metasurfaces and optical waveguides offers a promising approach to manipulate light across multiple degrees of freedom at high speed in compact photonic integrated circuit (PIC) devices. Here, we demonstrate a gigahertz-rate-switchable wavefront shaping by integrating metasurface, lithium niobate on insulator photonic waveguides, and electrodes within a PIC device. As proofs of concept, we showcase the generation of a focus beam with reconfigurable arbitrary polarizations, switchable focusing with lateral focal positions and focal length, orbital angular momentum light beams as well as Bessel beams. Our measurements indicate modulation speeds of up to the gigahertz rate. This integrated platform offers a versatile and efficient means of controlling the light field at high speed within a compact system, paving the way for potential applications in optical communication, computation, sensing, and imaging.

We present our efforts towards power scaling of Er:Lu₂O₃ lasers at 2.85 µm. By applying a dual-end diode-pumped resonator scheme, we achieve an output power of 14.1 W at an absorbed pump power of 59.7 W with a slope efficiency of 26%. In a single-end pumped resonator scheme, an output power of 10.1 W is reached under 41.9 W of absorbed pump power. To the best of our knowledge, this is the first single crystalline mid-infrared rare-earth-based solid-state laser with an output power exceeding 10 W at room temperature.

Employing couplers to convert guided waves into free-space modes and flexibly control their wavefront is one of the key technologies in chip-integrated displays and communications. Traditional couplers are mainly composed of gratings, which have limitations in footprint, bandwidth, as well as controllability. Though the resonant/geometric metasurface newly emerges as a promising interface for bridging guided waves with free-space ones, it either relies on complex optimizations of multiple parameters, or is subject to the locked phase response of opposite spins, both of which hinder the functional diversity and practical multiplexing capability. Here, we propose and experimentally demonstrate an alternative with a spin-decoupled meta-coupler, simultaneously integrating triple functions of guided wave radiation, polarization demultiplexing, and dual-channel wavefront manipulation into a single device. By endowing polarization-dependent functionalities into a pure geometric metasurface, the out-coupled left-handed and right-handed circular polarization guided waves intelligently identify the predesigned phase modulation and reconstruct desired wavefronts, like bifocal focusing and holography multiplexing, with a polarization extinction ratio over 13.4 dB in experiments. We envision that the robust, broadband, and multifunctional meta-coupler could pave a way for the development of versatile multiplexed waveguide-based devices.