摘要: Nowadays, optical sensing or imaging application aims at higher level of integration and sensitivity. To address photon-sparse sensing scenarios, single-photon avalanche diodes (SPADs) are being widely adopted, while to address integration, silicon photonics becomes the main driver.

In the first part of my talk, I will demonstrate a high performance Si-based SPAD. SPADs have been widely used in research and industry for single-molecule fluorescence, bio-medical imaging, quantum key distribution and depth sensing (e.g., LiDAR), because of its high sensitivity and picosecond timing resolution (i.e., low jitter). In addition, Si-based SPAD stands out due to its low cost, compact form factor, ease of integration, and compatibility with standard CMOS fabrication techniques. Yet the actual application of Si-based SPADs are limited by its current trade-off between efficiency and timing. Light trapping method helps break the trade-off, in that nano-optics enables manipulation of photons. I will go through the design, simulation, fabrication and characterization of light trapping SPAD.

For the second part of my talk, I will demonstrate sensing or imaging applications based on silicon photonics and SPADs. This includes a micro-ring based sensing platform with an integrated Ge photodetector, which serves point-of-care application. In addition, a SPAD based transient imaging setup will be shown to record photon propagation at a 300ps time scale. Due to their CMOS compatibility, both applications have the potential of being massly and cheaply produced.

报告人简介：臧凯，男，出生于1989年6月。2007年本科求学于北京大学信息科学技术学院电子学系，2011年研究生和博士求学于斯坦福大学电子工程系，2017年6月毕业。博士生导师为美国工程院院士James Harris 教授。臧凯的研究课题集中在硅基光电子领域，包括针对激光雷达和医疗的高性能的单光子探测器（SPAD，文章发表于Nature Communication杂志），利用硅锗外延技术的片上光互联及生化检测芯片，以及基于SPAD的成像系统和算法优化。

臧凯毕业后在微软总部西雅图Hololens 虚拟现实产品组负责光学显示和传感的研发工作。2018年6月离职并创立灵明光子科技有限公司，任职CTO。公司业务聚焦于低成本高性能的SPAD芯片及解决方式，应用于激光雷达、手机以及医疗领域。