Interference of Resonant and Nonresonant Three-Wave Mixing in Diamond

Abstract

We have used the second harmonic of a Nd: glass laser and a continuously tunable dye laser to measure the variation of the third-order nonlinear susceptibility ${|{\ensuremath{\chi}}^{(3)}(\ensuremath{-}2{\ensuremath{\omega}}_{1}+{\ensuremath{\omega}}_{2}, {\ensuremath{\omega}}_{1}, {\ensuremath{\omega}}_{1}, \ensuremath{-}{\ensuremath{\omega}}_{2})|}^{2}$ when ${\ensuremath{\omega}}_{1}\ensuremath{-}{\ensuremath{\omega}}_{2}$ passes through the optical-phonon resonance in diamond. The frequency difference between the observed maximum and minimum determines the nonlinear electronic susceptibility ${\ensuremath{\chi}}^{(3)E}$ both in sign and magnitude with respect to the Raman susceptibility. A theoretical discussion of this interference is presented.