Novel, High-power, Mid-infrared Optical Source for the 5-12 Micron Spectrum

This project has led to important new advances in coherent near to mid infrared light sources on several fronts. By exploiting nonlinear frequency down-conversion techniques based on optical parametric generation and oscillation, we have developed several novel optical sources in different time scales and operating regimes with extended tuning throughout the 1.4 4.2 microns spectral range in the near to mid IR and 6 6.8 microns in the deep mid infrared. The developed devices exploit the new generation of QPM and mid IR nonlinear crystals of MgOPPLN, MgOsPPLT, and CdSiP2 together with fiber and solid-state laser technology at 1064 nm as the pump source, resulting in compact, practical, and portable device architectures for many real applications. We have achieve record optical powers of 17 W in cw operation and average powers up to 12 W in the ultrafast picosecond regime at 80 MHz high repetition-rate, covering the spectral range of 1.4 4.2 microns. In the deep mid IR, we have achieved record pulse energies as much as 1.5 mJ at repetition rates as high as 450 MHz, with spectral coverage across 6 6.8 microns. The developed systems have provided a viable new class of tunable coherent light sources for previously inaccessible spectral regions in the near to mid infrared offering record optical powers and pulse energies. With the exploitation of mid IR optical crystals of ZnGeP2 and OPGaAs of high optical quality in cascaded pumping schemes using the near to mid IR parametric sources developed during this project, further wavelength extension into the 5 12 microns spectral range will be feasible. The exploitation of newly emerging Tm fiber laser technology near 2 microns also offers great potential for direct generation of tunable coherent radiation at unprecedented optical powers in the 5 12 microns spectral range using one-step parametric generation in the nonlinear crystals of ZnGeP2, CdSiP2, and OP GaAs.