Abstract

The possibility of achieving large phase shift at reasonable powers has revived interest in cascaded quadratic interactions, where a fundamental frequency (FF) field may acquire a nonlinear phase change interacing with the generated second-harmonic (SH) [1]. This effect has been mainly described in the assumption that only a FF and a SH scalar field interact through an effective nonlinearity [2]. Hereby we demonstrate that the onset of spatial chaos poses fundamental limitations to the efficiency of SH generation and to the use of a coherent SH seed in phase sensitive modes of operations [3, 4]. Moreover, we point out that vectorial interactions generalize the cascading effect based on the scalar approach, since two orthogonal FF beams may acquire energy from one another through a process which implies the conversion to the SH field as an intermediate step. When this polarization cascading is exploited for all-optical devices [5, 6], it is crucial to establish the conditions for which the field evolutions remain regular.

© 1995 Optical Society of America