Midwave infrared OPO pumped by a compact, efficient Tm laser

We propose the development of a MWIR system comprised of a diode-pumped, Q-switched, Tm laser pumping an OPO, which yields signal and idler waves that are both in-band to the atmospheric windows of interest (3.5 to 4.1 and 4.4 to 5.0 microns). The primaryimprovement over previous work, in our view, is that we have provided the necessary 2-micron pump laser for the OPO by directly Q-switching a Tm laser rather than using the Tm laser as an optical pump for a separate Ho laser. This eliminates one conversionstep and substantially reduces the optical complexity of the system. The all-Brewster, side-pumped-slab gain module and its concomitant benefits will allow us to obtain efficient, reliable, Q-switched, TEM00 operation in a configuration that is lesscostly, more compact, and more robust laser than previously demonstrated MWIR sources. Specifically, we believe that our single-slab gain module, configured in the proposed all-Brewster, Tm:YALO geometry, pumped by two 60-W diode bars will yield 40 W ofQ-switched, 2-micron output at 20 kHz. This pump source will, in turn, generate a total OPO output of 20 W, ~10 W in each of the two desired atmospheric windows. The development of a MWIR OPO-based source would add a new and strongly desired capability to existing remote-sensing technologies, by providing an alternative to the FTIR technology that has been well accepted in the commercial (rather than research)market for remote sensing. Given success in the overall proposed SBIR effort, Q-Peak would attempt to develop a commercial OPO-based instrument for gas concentration monitoring. We believe customer acceptance of such systems will occur given theirsimilarity but clear advantages over installed FTIR devices. In addition, the OPO source would provide a path for Q-Peak to enter the industrial process control market, a large and growing business.