Optical parametric generation of greater than 30 mJ signal energies in PPLN stacks

Summary form only given. Coherent mid-infrared (IR) radiation sources with high pulse energies and good beam quality are needed for a variety of remote sensing applications. In this paper we report the generation of high-energy mid-IR pulses by pumping stacks of PPLN crystals with multiple elliptical beams in a single-pass optical parametric generator (OPG) configuration. Signal energies as high as 33 mJ in 3.5-ns pulses were achieved with bare (i.e., uncoated) PPLN crystals while maintaining excellent beam quality. To the best of our knowledge these are the highest mid-IR signal energies ever generated with nanosecond pulses in uncoated PPLN crystals, but this system should easily be scaleable to generate much higher signal energies.