Research On 526mJ Subnanosecond Hybrid-pumped Nd:YAG Laser

Solid-state sub-nanosecond lasers with high pulse energy are of great interest for applications in various fields such as laser-induced periodic surface structures(LIPSSs),material processing,shock ignition,nonlinear optics and biomedicine.Particularly in laser processing,lasers in hundreds of picoseconds with high energy of joule level have the merits of small scope of thermal effect,high precision and high speed.Theoretical and experimental research is carried on by passively Q-switched and master oscillator power amplifier(MOPA)in order to obtain the laser system with high pulse energy and narrow pulse width.At first,the paper introduces the development of Solid-state sub-nanosecond lasers with high pulse energy at home and abroad.The physical characteristics and energy level structure of Cr:YAG saturation absorber are described.In different initial transmittance situations,we simulated how the transmittance of Cr:YAG varies with the pump light power density.The theoretical calculation results of the passive Q-switched pulse width are obtained by solving the rate equation of passively Q-switching.The laser amplification mechanism of the main oscillator power amplifier is introduced,and the output energy and energy gain of the amplifier were solved theoretically.The energy extraction efficiency of single-pass and double-pass amplifier is calculated theoretically.The design and theoretical verification of pulse laser oscillator and amplifier are carried out.These include the relevant parameters of the passive Q-switched gain medium and the saturable absorber,and the selection and design of single-lamp double-rod amplifier and external-cavity-frequency crystal.This paper focuses on the compensation of the heat effect of the xenon lamp pumping.Theoretical simulation and verification of different degrees of thermal effect compensation are carried out with optical simulation software(re Zonator).In this paper,a laser system with a passive Q-switched microchip laser for seed light and a single xenon lamp pumping double crystal amplifier are designed and developed.For input pulse energy of 141?J with pulse duration of 754 ps,the pulse laser system delivers526 m J pulse energy and 728 ps pulse width output at 10 Hz with pulse profile shape preservation.The energy stability of the laser pulse is less than 3%,and the beam quality factor M2 is less than 2.26.