Narrow line-width, high-energy, 2-micron laser for coherent wind lidar

Summary form only given. 2 mum solid-state lasers are the primary choice for coherent Doppler wind detection. As wind lidars, they are used for wake vortex and clear air turbulence detection providing air transport safety. In addition, 2 mum lasers are one of the candidates for CO₂ detection lidars. The rich CO₂ absorption line around 2 m, combined with the long upper state lifetime, has made Ho based 2 mum lasers a viable candidate for CO₂ sensing DIAL instrument. As a transmitter for a coherent wind lidar, this laser has stringent spectral line width and beam quality requirements. The laser architecture is composed of a seed laser, a ring oscillator, and a double pass amplifier. The seed laser is a single longitudinal mode with a line width of 13 KHz. The 100 mJ class oscillator is stretched to 3 meters to accommodate the line-width requirement without compromising the range resolution of the instrument. The amplifier is double passed to produce greater than 300 mJ energy. This system is hardened for ground as well as airborne applications.