End-pumped Monoblock Laser for Eyesafe Targeting Systems

We describe a next-generation monoblock laser capable of greater than 10 mJ, 1.5 μm output at 10 pulses per second (PPS) over broad ambient temperature extremes with no active temperature control. The transmitter design is based on a Nd:YAG laser with a Cr 4+ passive Q-switch and intracavity KTP OPO. In order to achieve the repetition rate and efficiency goals of this effort, but still have wide temperature capability, we are endpumping the Nd:YAG slab with a 12-bar stack of 100 W (each) diode bars. We compare different techniques for focusing the pump radiation into the 4.25 mm x 4.25 mm end of the slab, including a lensed design, a reflective concentrator, and a lens-duct. We demonstrate widetemperature operation (-20 to 50 degrees Celsius) for each end-pumped configuration.