Multi-pulse laser generation based on programming diffraction loss of acousto-optic Q-switched RF excited waveguide CO lasers.

Acousto-optic Q-switched (AOQ-switched) lasers always suffer from having a laser pulse with a long tail and lower energy utilization. The ability of an acousto-optic modulator (AOM) to quickly program diffraction losses provides an effective method to solve these problems. In this paper, a six-temperature model is built to analyze the dynamical properties of the AOQ-switched laser with programmable control of the diffraction loss. The AOQ-switched laser pulse, or even the multi-pulse without a tail, can be achieved by precise adjusting of the delay time, pulse width, and pulse interval of the AOM control signal within a laser cycle. In the experiments, when the pulse width of the AOM control signal is reduced to 1 µs, the AOQ-switched laser pulse without the tail is obtained with a peak power of 1.36 kW and a pulse width of 132 ns at the repetition of 5 kHz. Meanwhile, equal energy double-pulse, triple-pulse, and quadruple-pulse lasers can be achieved by precisely programming the delay time and pulse interval of the AOM control signal. The average power has been significantly improved.