Abstract

It is generally accepted¹ that a second harmonic signal cannot be generated or amplified in an isotropic material due to symmetry conditions that result in all even orders of the nonlinear susceptibility vanishing. In materials with nonvanishing χ⁽²⁾. dispersion also requires that the material be biréfringent in order for the second harmonic process to be phase matched. We present a novel scheme in which amplification of a second harmonic signal can be accomplished in an isotropic material through use of the nonvanishing χ⁽⁵⁾ of the material, and phase matching is satisfied by adjusting the angle between the signal and pump.

© 2001 Optical Society of America