<title>Multimode dynamics of a sinusoidally modulated, diode-pumped Nd:YAG laser</title>

Abstract

Pump modulation is used to explore multimode interactions in an standing-wave Nd:YAG laser. Large amplitude modulation drives the system into apparent period doubling cascades and chaos as are expected for the nonlinear oscillations of the driven relaxation oscillations of the laser. However, examination of the intensity fluctuations and intensity power spectra of individual modes indicates that anti-phased fluctuations and subharmonic resonances are quite common and that they masquerade as simpler period-doubling phenomena. Even the sinusoidal response of a multimode laser to weak modulation is found to reveal multimode couplings in the distortions of the resonant frequency and width of the resonance as the pump current is raised, bringing more modes into the dynamics and strengthening the side modes.