Optical neural networks (ONNs), enabling low latency and high parallel data processing without electromagnetic interference, have become a viable player for fast and energy-efficient processing and calculation to meet the increasing demand for hash rate. Photonic memories employing nonvolatile phase-change materials could achieve zero static power consumption, low thermal cross talk, large-scale, and high-energy-efficient photonic neural networks. Nevertheless, the switching speed and dynamic energy consumption of phase-change material-based photonic memories make them inapplicable for in situ training. Here, by integrating a patch of phase change thin film with a PIN-diode-embedded microring resonator, a bifunctional photonic memory enabling both 5-bit storage and nanoseconds volatile modulation was demonstrated. For the first time, a concept is presented for electrically programmable phase-change material-driven photonic memory integrated with nanosecond modulation to allow fast in situ training and zero static power consumption data processing in ONNs. ONNs with an optical convolution kernel constructed by our photonic memory theoretically achieved an accuracy of predictions higher than 95% when tested by the MNIST handwritten digit database. This provides a feasible solution to constructing large-scale nonvolatile ONNs with high-speed in situ training capability.

针对红外图像和可见光图像的融合目标检测问题，提出一种基于双模态融合网络的目标检测算法。在同时输入红外和可见光图像对后，利用设计的红外编码器提取红外图像空间特征信息；通过设计的可见光编码器将可见光图像从垂直和水平两个空间方向聚合特征，通过精确的位置信息对通道关系进行编码；最后，采用提出的门控融合网络自适应调节两路特征的权重分配，实现跨模态特征融合。在KAIST行人数据集上，与基准算法YOLOv5-n单独检测可见光图像和红外图像的结果相比，所提算法检测精度分别提升15.1%和2.8%；与基准算法YOLOv5-s相比，检测精度分别提升14.7%和3%；同时，检测速度在两个不同基准算法模型上分别达到117.6 FPS和102 FPS。在自建的GIR数据集上，所提算法的检测精度和速度也同样具有明显优势。此外，该算法还能对单独输入的可见光或红外图像进行目标检测，且检测性能与基准算法相比有明显提升。

为了提高多像素光子计数器（MPPC）的高速探测并改善光子数分辨特性，采用门控抑制的MPPC，并通过自平衡及低通滤波相结合的技术手段，将MPPC的容性尖峰噪声抑制到热噪声水平，在实现光生雪崩信号的线性提取的同时快速恢复探测。实验结果表明，200 MHz门控的MPPC实现了40 MHz重复频率激光下14个光子的有效分辨，平均每脉冲光子数高达6.8。与被动抑制模式相比，200 MHz正弦门控模式下的光子数分辨效果明显得到了改善，为高速光子数可分辨探测提供了参考。

This work reviews the state-of-the art multi-gate field-effect transistor (MuGFET) process technologies and compares the device performance and reliability characteristics of the MuGFETs with the planar Si CMOS devices. Owing to the 3D wrapped gate structure, MuGFETs can suppress the SCEs and improve the ON-current performance due to the volume inversion of the channel region. As the Si CMOS technology pioneers to sub-10 nm nodes, the process challenges in terms of lithography capability, process integration controversies, performance variability etc. were also discussed in this work. Due to the severe self-heating effect in the MuGFETs, the ballistic transport and reliability characteristics were investigated. Future alternatives for the current Si MuGFET technology were discussed at the end of the paper. More work needs to be done to realize novel high mobility channel MuGFETs with better performance and reliability.

Optical detectors with single-photon sensitivity and large dynamic range would facilitate a variety of applications. Specifically, the capability of extending operation wavelengths into the mid-infrared region is highly attractive. Here we implement a mid-infrared frequency upconversion detector for counting and resolving photons at 3 μm. Thanks to the spectrotemporal engineering of the involved optical fields, the mid-infrared photons could be spectrally translated into the visible band with a conversion efficiency of 80%. In combination with a silicon avalanche photodiode, we obtained unprecedented performance with a high overall detection efficiency of 37% and a low noise equivalent power of 1.8×10-17W/Hz1/2. Furthermore, photon-number-resolving detection at mid-infrared wavelengths was demonstrated, for the first time to our knowledge, with a multipixel photon counter. The implemented upconversion detector exhibited a maximal resolving photon number up to 9 with a noise probability per pulse of 0.14% at the peak detection efficiency. The achieved photon counting and resolving performance might open up new possibilities in trace molecule spectroscopy, sensitive biochemical sensing, and free-space communications, among others.

采用图像探测器的角位移测量技术可实现高精度高分辨力角位移测量。为提高角位移测量装置的鲁棒性，本文设计了一种自适应安装的高精度图像式角位移测量装置。其装调过程非常简便，且可以保证在标定光栅存在偏心时具有高分辨力和高精度测量输出。首先，提出了基于双线阵图像传感器的测角装置设计原理，并设计了单圈绝对式标定光栅。然后，采用基于质心算法的高分辨力细分算法进行细分，并采用双线阵图像传感器对测角误差进行误差补偿。最后，设计实验装置测试自适应安装的性能。实验结果表明，当标定光栅的偏心度在±1 mm以内时，所设计装置可以实现高精度和高分辨力的角位移测量。本文所设计的装置可以在标定光栅存在±1 mm的安装偏心时保证输出精度，为小型角位移测量装置适应性的提高给出了解决方案。