Title of Presentation: Progress of 2-micron Detectors for Application to Lidar Remote Sensing

Primary (Corresponding) Author: Nurul Abedin

Organization of Primary Author: Langley Research Center

Co-Authors: Tamer F. Refaat, Syed Ismail, Grady Kocha, Upendra N. Singha

Abstract: AlGaAsSb/InGaAsSb heterojunction phototransistors were developed at Astropower, Inc under Laser Risk Reduction Program (LRRP) for operation in the 2-um region. These phototransistors were optimized for 2-µm detection and have high quantum efficiency (> 60%), high gain (> 1000) and low noise equivalent power (NEP~5E-14 W/(sqrt.Hz)), while operating at low bias voltage. One of these phototransistors was tested in the 2-um CO2 Differential Absorption Lidar (DIAL) system currently under development under the Instrument Incubator Program (IIP) at NASA Langley. Lidar measurements included detecting atmospheric structures consisting of thin clouds in the mid-altitude and near-field boundary layer. These test results are very promising for the application of phototransistors for the two-micron lidar remote sensing. In addition, avalanche photodiodes (APD) acquired from Raytheon were used in atmospheric testing at 2-um. A discussion of these measurements will also be presented in this paper.