High Average Power Q-switched Diode-Pumped Yb:YAG Laser

We propose to develop a compact, high-average-power, high-repetition-rate, Q-switched diode-pumped Yb:YAG laser for applications such as target illumination from airborne and ground based mobile platforms. An innovative double TIR laser-head design willbe utilized to provide >150W of average power at high repetition rates (2 to 10 kHz), and TEM00 mode operation in all regimes. Strong, broad absorption bands of the Yb:YAG crystals allow pumping by efficient, robust, commercial, InGaAs laser diodes. Thethermal load on the crystal is very low because of the small quantum deficit between the pump wavelength (940nm) and the laser output (1030nm). Diffraction limited laser beam (TEM00 mode), and stable Q-switched pulses of > 80mJ/pulse will be produced at2kHz pulse repetition frequency (PRF) with a conversion efficiency of > 10%. At 10kHz PRF ~15mJ/pulse is expected with the same beam quality. The simple and compact configuration of the laser head along with high conversion efficiency and low thermalload will result in a small laser system suitable for airborne and mobile applications. In Phase I, a comprehensive design of the laser will be performed, and a bread-board high PRF Yb:YAG laser will be demonstrated. In Phase II a full scale prototypelaser system will be developed. In addition to the military applications other anticipated commercial applications are for materials processing, lidar, remote sensing and detection, a high- average power source for efficient frequency conversion.