Description: Thulium doped fiber laser near 2 micron is of great interest because of the prospect of combining high efficiency, high output power, and retina safety together. This proposal is for the development of highly efficient 1.94 micron fiber laser as the pumping source of Ho doped crystal lasers for LASA's lidar applications. New Tm-doped glasses and fibers will be developed, high efficient fiber lasers will be demonstrated, and a new laser configuration suitable for NASA's application will be designed and demonstrated.

Benefits: Pulsed laser at 2.05 micron wavelength can be used in a Differential Absorption Lidar (DIAL) to make precise, high-resolution CO2 measurements to investigate sources, sinks, and fluxes of CO2, particularly across the mid to lower troposphere. NASA Needs 2.05μm laser transmitter with high efficiency and high output power. NASA needs 1.94 micron fiber laser as the pump source for the 2.05 micron laser transmitter because it offers several significant advantages including high electrical efficiency, low thermal load, compact size, low mass, long-lifetime, and rugged package.

This eye-safe laser source can be used to build commercial lidar for ranging and surface topography applications, be used as the light source for fiber optical sensing, fast scanning biomedical imaging, and scientific research. Such a fiber laser is of great interest because of the potential possibility of combining high efficiency, high output power, and retina safety together, especially for materials processing. Due to the stronger absorption of many materials containing water molecules and organic materials at 2 micron than at 1 micron, less power of 2 micron fiber laser is needed compared to 1 micron fiber laser in order to achieve the same effect.