Research activities to further develop the technology of broadly tunable femtosecond optical parametric oscillators (fs OPO s) for ultrafast studies will be initiated. In order to extend the tuning range for fs OPO applications beyond the limit of the current operating range, from 3.65 um to the 15-20 um range, it is proposed (1) to search for new nonlinear optical crystals such as mixed KTP-isomorphs and (2) to evaluate known nonlinear crystals. The theoretical foundation of the physics of the pulse formation process in fs OPO s will also be investigated. Coherent ultrafast pulse sources could have applications in semiconductor physics, engineering, chemistry and biology. Semiconductor interactions in the 3-5 um range will be investigated.
