Optical Parametric Scattering in Ammonium Dihydrogen Phosphate

This paper presents a detailed experimental study of spontaneous parametric scattering in the optical region in ammonium dihydrogen phosphate (ADP) pumped with a pulsed laser source at 3472 {}. The dependence of the process on crystal orientation, observation direction, pump power, crystal length, and detector aperture, and the properties of bandwidth and intensity of the scattered radiation, were measured and compared with predictions of a detailed theory by Giallorenzi and Tang. The parametric process covers a wide range of visible and infrared wavelengths and can be observed over a rather large range of observation directions. For a peak power of 1 MW of the pump, about 1-10 {μ}W of scattered radiation was obtained in a 1-cm-long crystal with a detector aperture of about 10^-4 sr.