A large area, high speed photodetector for a microwave modulated hybrid lidar-radar application

摘要

For microwave modulated lidar applications, a large area photodetector with low noise, high gain, and a bandwidth of a few gigahertz is needed. The photodetector presented is a vacuum photodiode that employs a planar 300 /spl mu/m/sup 2/ metal-semiconductor-metal device as the anode to increase the response speed. This is the first known use of a metal-semiconductor-metal device under electron bombardment. The photodetector has an 8 mm active area, noise figure less than 1.5 dB, gain greater than 10/sup 3/, and an expected bandwidth exceeding 3 GHz.