Optical harmonic generation in two ferroelectric crystals

Abstract

The generation of the optical second harmonic by nonlinear dielectric response has been studied in crystals of guanidine aluminum sulfate hexahydrate (GASH) and triglycine sulfate (TGS). Optically, these crystals are uniaxial and biaxial, respectively. Crystal orientations and optical polarizations which maximized the traveling-wave interaction between the fundamental and harmonic were predicted on the basis of the birefringence and the nonlinearity tensor, and verified experimentally with a ruby optical maser. Two polarization arrangements for the maser signal in the crystal were demonstrated: a single plane polarized wave, or two waves polarized at right angles and traveling at different velocities. The harmonic output for GASH and TGS was a factor of 30 to 1000, respectively, below that for potassium dihydrogen phosphate (KDP). © 1964 Optical Society of America.