Abstract

Recently there has been increasing interest in obtaining large nonlinear phase shifts by an effective intensity dependent refractive index n₂ based on second-order nonlinearities. These phase shifts arise as down-conversion of the second harmonic, away from perfect phase-matching, to the fundamental, which in general is out of phase with the fundamental source field. This process has been termed cascaded,^1,2 as it involves the consecutive application of second-order nonlinearities χ⁽²⁾(ω,ω):χ⁽²⁾(^—ω,2ω).

© 1994 IEEE