Study On The Technology Of Producing Nanosecond Interval Pulse Group Laser By Acousto-optic Control

With the development of laser plasma resolution,medical treatment,laser precision processing and other fields,the demand for high repetition rate,high peak power,and narrow pulse interval of pulse group lasers is increasing day by day.In response to the current lack of means to obtain high repetition rate,high peak power pulse group lasers,this paper uses acousto-optic Q-switching to achieve high repetition rate pulse group laser output,Using multi-step Q-switching method to achieve high repetition rate nanosecond interval pulse group laser output.A new scheme for obtaining multi pulse laser output through single energy storage using the method of acoustic optical multi-step Q-modulation.Based on the theoretical analysis of acousto-optic Q-switching,the relationship between the diffraction efficiency of acousto-optic driver and the loss in the resonant cavity is established.Finally,the rate equation related to the time term is deduced,and the relationship between the Q-switching time and the number of particles and photons in the cavity is simulated,providing a theoretical basis for subsequent experiments.In the experimental research,a conventional acoustooptic Q-switched laser experimental platform was first established to analyze and study the output characteristics of a single pulse laser under the acoustooptic driving signal voltage,laying a foundation for subsequent multi-pulse experiments.Then,the step signal is changed for dual pulse laser output and three pulse laser output experiments,and the pulse width and average energy of the pulse laser output are measured and analyzed,as well as the influence of different step signal parameters on the sub pulse interval.Realize acousto-optic regulation to obtain pulse group laser output with high repetition rate and high peak power nanosecond interval.The shortest subpulse interval is 766 ns,and the pulse group has an equal height three pulse output.The repetition frequency is 34 k Hz,the average power of the pulse group is 6.12 W,the optical to optical conversion efficiency is 22.03%,the average pulse width is 16.82 ns.