Second-harmonic generation properties of 2-amino-5-nitropyridinium-dihydrogenarsenate and -dihydrogenphosphate organic-inorganic crystals

We present a comparative study of the linear and nonlinear optical properties of two isomorphous organic-inorganic crystals: the 2-amino 5-nitropyridinium-dihydrogenphosphate (2A5NPDP) and -dihydrogenarsenate (2A5NPDAs). We determine accurate equations for the dispersion in wavelength of their principal refractive indices from direct prism measurements and from angular noncritically phase-matched second-harmonic generation (SHG) experiments. We deduce the quadratic nonlinear coefficients d/sub 15/ and d/sub 24/ of each compound from the phase-matched conversion efficiency of SHG experiments and find that they are close to those of KTiOPO/sub 4/.