Invited Speakers

 

Nam Donguk
Asst Prof, EEE, NTU

Title: Low-Threshold Germanium Laser for Chip-Scale LiDAR

Abstract: LiDAR (Light Detection and Ranging) is an imaging system central to autonomous vehicles. The sizes of all the present LiDAR systems are inevitably huge and their prices are costly since they comprise of discrete, bulky, and expensive optical components such as lasers and photodetectors that enable the creation of 3D maps around a vehicle by sending highly directional light beams and detecting the reflected ones. Over the past few years, there have been relentless efforts from all over the world in revolutionizing LiDAR systems in size and cost by putting all the necessary optical parts on a tiny silicon chip. However, the dream of an ultra-compact, low-cost chip-scale LiDAR has seemed so far away because of the absence of a low-threshold laser on silicon—the most crucial component for LiDAR.

In this talk, we will present our recent result on germanium lasers on silicon that operate at a low threshold. We will first introduce our innovative strain engineering platforms that can create direct bandgap germanium nanowires by inducing >5% elastic tensile strain. Then, we will present our first experimental observation of low-threshold optically pumped lasing in highly strained germanium nanowires. We will end this talk by discussing the potential and future works of our strain-engineered germanium lasers for the ultimate realization of chip-scale LiDAR systems.

Biography: Dr. Donguk Nam received his Ph.D. (2014) and M.S. (2012) degrees both in Electrical Engineering from Stanford University, and obtained his B.Eng. degree from Korea University (2009). After working as a postdoctoral scholar at Stanford University for one year, he joined Inha University, South Korea, as an Assistant Professor. In August 2017, he joined the school of EEE at NTU as an Assistant Professor.