9361987 Caughey We propose the design, construction and evaluation of a 3-12 um narrowband light source based on an optical parametric oscillator/optical parametric amplifier pair (OPO/OPA), consisting of ZnGeP, crystals that are pumped by a tunable Kl P OPO. The tunable KTP OPO, which is itself pumped by a Nd:YAG laser, provides a novel method not only for pumping the ZnGeP2 OPO, but for providing an additional option for tuning and for characterizing it. Means for narrowing the limewidth of the ZnGeP2 OPO will be evaluated. Since femtosecond and picosecond Nd:YAG lasers are available. the proposed system can lead to an ultrafast tunable IR source. The proposed Phase I program is expected to provide the technical base for the manufacture of a long sought 3- 12 um tunable laser source. ***