Single Frequency Lasers for Space-Based Wind and Aerosol Lidar

Stable, single-frequency cw lasers operating at 2 µm and at 1064/532/355 nm are needed in a number of lidar systems that are being planned for NASA airborne and space-based lidar systems. These include the following. 1. Direct Detection Doppler Wind Lidar systems that operate at 355 nm. 2. Coherent Wind Lidar systems that operate at 2 µm. 3. High Spectral Resolution Lidar systems that operate at 1064/532/355/nm. 4. Ozone DIAL systems. At least two missions that have been recommended by the NRC Earth Science Decadal Survey will need the technology that we propose to develop. These are the 3D-Winds mission and the ACE (Aerosol/Clouds/Ecosystems) mission. In our Phase 1 SBIR we successfully completed proof of principle demonstrations of the desired cw single-frequency lasers. Our approach for the 2 µm source was a compact linear resonator that demonstrated 65 mW of single frequency output compared to a goal of 20 mW. Our approach for the 1064/532/355 nm source was intracavity second and third harmonic generation in a compact 1064 nm ring laser that demonstrated simultaneous single-frequency outputs of 520 mW at 1064 nm, 240 mW at 532 nm, and 1.9 mW at 355 nm. The goal was > 1 mW at 355 nm. For Phase 2 we propose to build more hardened engineering demonstration units of the lasers, to develop electronics that could be readily transitioned to radiation hardened designs, and to demonstrate a frequency locking module for the 1064/532/355 nm source. We expect both lasers to be at a TRL of 5 at the completion of the Phase 2 work.