Antiphase states of sub-nanosecond Cr,Yb:YAG microchip self-Q-switched multimode laser

The antiphase states were observed experimentally in a laser-diode pumped sub-nanosecond microchip Cr,Yb:YAG self-Q-switched multimode laser which is resulted from the spatial hole burning effect. The stable two-mode, and three-mode oscillation are obtained with the increase of the pump power ratio. The modified multimode rate equations including the spatial hole-burning effect in the active medium and the non-linear absorption of the saturable absorber is proposed. The numerical simulations of the antiphase dynamics of such laser are in good agreement with the experimental data and the antiphase dynamics was explained by the evolution of the inversion population and the bleaching and recovery of the inversion population of the saturable absorber.