CASCADED 2ND-ORDER EFFECTS IN N-(4-NITROPHENYL)-L-PROLINOL, IN A MOLECULAR SINGLE-CRYSTAL

In investigation of cascaded second-order optical effects resulting in effective third-order interactions, temporal and spatial self-action, are presented for N-(4-nitrophenyl)-L-prolinol (NPP) a molecular sing le crystal with one of the largest phase-matchable second-order nonlin ear coefficients known in the visible and near-infrared portions of th e spectrum. We emphasize the effects of temporal and spatial walk-off in the nonlinear-optical propagation in NPP and discuss their conseque nces for cascaded second-order nonlinear applications. Walkoff effects play a detrimental role in cascaded all-optical switching. Whereas in standard second-harmonic generation walk-off reduces the efficiency b ut does not prevent the generation, in the case of cascading back-conv ersation is required and more-deleterious effects occur: a portion of the held is lost in that the overlap between fundamental and second-ha rmonic wavelengths is reduced. (C) 1997 Optical Society of America.