Interest is rapidly growing in eye-safe solid-state lasers for range finding, LIDAR, infrared countermeasures, medicine, dentistry, and others. To address the need for compact, high efficiency lasers operating in this important spectral band, an ultra-compact turnkey, narrow-band, high-mode-quality, high-pulse-energy, and high-pulse-repetition-frequency (PRF), diode-pumped solid-state (DPSS) pulsed laser system will be developed that, due to superior near infrared (NIR) absorption characteristics, high phonon energies, and good thermal characteristics, can be used in an optically thin configuration, which, when properly designed, including using a directly-mounted thermally conductive index matched window, allows for very high average power in the 1500 1600-nm spectral band. The laser is based on a new material system. The new innovative laser will be shown to best satisfy NASA remote sensing, mapping, and navigation and hazard avoidance applications by offering 0.2 mJ 2 mJ (1550 nm) at pulse rates from 10 Hz to 100 KHz. In Phase I, existing analytical laser models will be updated, integrated with optical models, and a candidate laser design will be developed. The new laser material will then be configured in end-pumped passive- and actively-Q-switched laser designs, and the laser output as a function of pump power, pump energy, and pump repetition rate will be characterized.