Nonadiabatic effects in optical pattern formation

Summary form only given. Tuning instability leading to pattern formation in cavity nonlinear optics is generally described in terms of a tilted-wave mechanism that provides a simple geometric and linear picture of the fact that diffractive off-axis waves can fit the cavity resonance allowing maximum energy extraction from the medium. In mean-field models the tilted wave mechanism is effective solely when the resonated field is blue-shifted from the nearby cavity resonance. And off-axis waves are generally prevented on the other side of cavity resonance. A rather novel mechanism for pattern formation, that permits off-axis emission also on the red side of cavity resonance, is proposed and studied. This mechanism for off-axis wave emission occurs in presence of a time-varying periodic detuning; since this mechanism becomes ineffective when the modulation frequency of detuning is either fast or slow as compared to the typical relaxational dynamics of the system, it is referred as nonadiabatic. A detailed analysis of nonadiabatic effects on pattern formation are presented for the of a doubly-resonant degenerate optical parametric oscillator (DOPO).