Parametric resonance in a modulated microchip multimode laser

A nonlinear response of a laser-diode-pumped microchip LiNdP(4)O(12) (LNP) multimode laser that is subjected to multiple-frequency modulations is investigated. Clustering and breathing motions featuring intermode parametric resonances are demonstrated when the LNP laser was modulated by rational frequencies chosen to be nearly resonant to multiple relaxation-oscillation frequencies inherent in multimode lasers. A simple correspondence between the modulation signal patterns and the total-output power-spectrum patterns is demonstrated.