Nonlinear-laser effects in NH4H2PO4 (ADP) and ND4D2PO4 (DADP) single crystals: almost two-octave multi-wavelength Stokes and anti-Stokes combs, cascaded lasing in UV and visible ranges with the involving of the second and third harmonic generation

We report the experimental investigation of nonlinear cascaded lasing χ(3) ↔ χ(2) effects in UV and visible ranges and high‐order Stokes and anti‐Stokes generation covering spectral space of about 18000 cm–1 by stimulated Raman scattering and multi‐wave mixing processes under one‐micron picosecond pumping in the paraelectric state of NH4H2PO4 and ND4D2PO4 single crystals. All recorded Raman induced laser wavelengths are identified and attributed to their SRS‐promoting vibration modes. Brief review of nonlinear‐laser processes in non‐centrosymmetric phosphates of KH2PO4‐family and some physical properties of NH4H2PO4 and ND4D2PO4 are given as well. (© 2008 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)