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.