On-chip focusing of plasmons in graded-index lenses is important for imaging, lithography, signal processing, and optical interconnects at the deep subwavelength nanoscale. However, owing to the inherent strong wavelength dispersion of plasmonic materials, the on-chip focusing of plasmons suffers from severe chromatic aberrations. With the well-established planar dielectric grating, a graded-index waveguide array lens (GIWAL) is proposed to support the excitation and propagation of acoustic graphene plasmon polaritons (AGPPs) and to achieve the achromatic on-chip focusing of the AGPPs with a focus as small as about 2% of the operating wavelength in the frequency band from 10 to 20 THz, benefiting from the wavelength-independent index profile of the GIWAL. An analytical theory is provided to understand the on-chip focusing of the AGPPs and other beam evolution behaviors, such as self-focusing, self-collimation, and pendulum effects of Gaussian beams as well as spatial inversions of digital optical signals. Furthermore, the possibility of the GIWAL to invert spatially broadband digital optical signals is demonstrated, indicating the potential value of the GIWAL in broadband digital communication and signal processing.

介绍了光学相控阵激光雷达天线技术研究的国内外现状，阐述了其基本原理和系统组成，并对级联式的硅基光学相控阵激光雷达天线技术方案进行了分析，在此基础上开展了高密度低串扰波导阵列技术和层叠光学相控阵技术等关键技术攻关，获取了激光雷达系统的关键技术参数，并进一步阐述了需解决的技术问题，最后对该体制激光雷达的应用进行了展望。

为了降低零模波导照明系统的成本、缩小尺寸，设计并完成衍射光栅、光波导以及零模波导的片上集成，并对集成化芯片的微纳结构及性能进行验证。采用时域有限差分法对集成化芯片进行了仿真设计，基于微纳加工手段制备出片上衍射光栅、光波导以及零模波导阵列结构，对微观结构进行表征，并借助荧光微球对芯片的性能进行验证。通过荧光微球测试，制备的集成化芯片可以实现荧光微球的有效激发；通过微观结构表征，衍射光栅周期为（352.8±2.6） nm，齿宽为（155.3±2.4） nm，刻蚀深度为（67.8±3.5） nm；光波导芯层的宽度为（504.05±10.35） nm，高度为（184.9±8.9） nm；零模波导直径为（200.2±6.4） nm，深度为（301.3±7.6） nm，满足设计要求。芯片尺寸为22 mm×22 mm，最小线宽为155 nm，通过8个衍射光栅、约1 000条光波导以及数十万个零模波导阵列结构的片上集成，为零模波导的照明提供了一种紧凑且有效的解决方案。

Floquet topological insulators (FTIs) have been used to study the topological features of a dynamic quantum system within the band structure. However, it is difficult to directly observe the dynamic modulation of band structures in FTIs. Here, we implement the dynamic Su–Schrieffer–Heeger model in periodically curved waveguides to explore new behaviors in FTIs using light field evolutions. Changing the driving frequency produces near-field evolutions of light in the high-frequency curved waveguide array that are equivalent to the behaviors in straight arrays. Furthermore, at modest driving frequencies, the field evolutions in the system show boundary propagation, which are related to topological edge modes. Finally, we believe curved waveguides enable profound possibilities for the further development of Floquet engineering in periodically driven systems, which ranges from condensed matter physics to photonics.

Self-imaging is an important function for signal transport, distribution, and processing in integrated optics, which is usually implemented by multimode interference or diffractive imaging process. However, these processes suffer from the resolution limit due to classical wave propagation dynamics. We propose and demonstrate subwavelength optical imaging in one-dimensional silicon waveguide arrays, which is implemented by cascading straight and curved waveguides in sequence. The coupling coefficient between the curved waveguides is tuned to be negative to reach a negative dispersion, which is an analog to a hyperbolic metamaterial with a negative refractive index. Therefore, it endows the waveguide array with a superlens function as it is connected with a traditional straight waveguide array with positive dispersion. With a judiciously engineered cascading silicon waveguide array, we successfully show the subwavelength self-imaging process of each input port of the waveguide array as the single point source. Our approach provides a strategy for dealing with optical signals at the subwavelength scale and indicates functional designs in high-density waveguide integrations.