Power Laser for Eyesafe Coherent Lidar

High power diode-pumped 2 micron lasers are of great interest for a variety of lidar applications, including long range hard target tracking and space-based coherent laser radar systems operating in the eye-safe region of the spectrum. Lidar modeling suggests that 0.5-1 J/pulse energies at pulse repetition frequencies of about 40 Hz will be sufficient to meet many lidar mission requirements. CTI has recently conceptualized novel approaches to the development of efficient 2 micron lasers, and propose to extend current medium energy development work to the high pulse energy/high average power regime. Our numerical models indicate that a 0.5 J/pulse laser operating at 40 Hz repetition frequency (20W average power) with an electrical-to-optical efficiency of 5-10% in a simple oscillator configuration, is feasible to build with off-the-shelf components available today. This is a significant advance over realistic estimates of conventional oscillator/amplifier configurations. Key features of the novel designs are described in the proposal. During Phase I we propose to make detailed model calculations of laser performance, and provide a conceptual design of a demonstrator system. Efficient high power lasers will find uses as transmitters in lidar systems and as freestanding units. Lidar applications (long-range/high altitude wind mapping from the ground, in-situ high-altitude turbulence measurements, flood illumination imaging, etc.) exist for reduced eye hazard, high energy, high efficiency laser sources. The proposed lasers will also be well-suited for medical applications, as well as industrial applications. The laser will also prove useful as a 2 micron pump source for optical parametric oscillators operating in the 2 to 9 micron spectral range for DIAL applications.