Second-harmonic generation resonant to the 1<i>S</i>orthoexciton level of cuprous oxide

Abstract

The electric-quadrupole second-harmonic (SH) signal resonant to 1S yellow orthoexciton in ${\mathrm{Cu}}_{2}$O is observed. SH signals for the polycrystalline and the single crystal have been investigated. The polarization property of the SH signal has also been studied. The enhanced resonant SH signal can be ascribed to the small damping constant of the electric-quadrupole transition of the orthoexciton. The polarization properties of the SH signal are explained in terms of the energy consideration of the nonlinear optical properties of solids proposed by Pershan. In addition, resonant hyper-Raman scattering of the ${\mathrm{\ensuremath{\Gamma}}}_{12}^{\mathrm{\ensuremath{-}}}$ phonon is also observed. \textcopyright{} 1996 The American Physical Society.