Research On Pulse Single Longitude Mode Nd:YAG Laser Based On Double F-P Etalon

The single longitudinal mode laser has the advantages of ideal time and space waveform,high monochromaticity,highcoherence,and high beam quality.In the applications such as high-resolution laser spectroscopy,large area holography,precision measurement,gravitational wave detection,coherent beam synthesis,and laser guide star,single longitudinal laser source is equipped to meet the high requirement.By analyzing the generation principle of the longitudinal mode of the laser,understand several options for longitudinal mode and several types of mode selection methods are analyzed and compared,in this paper,the selection of the dual F-P etalon and the electro-optical Q-switching mode is adopted.Through the simulation of software such as Matlab,the model selection of double etalon was analyzed and the effect of the delay time of electro-optic Q-switching on the output of a single longitudinal mode laser.A double Fabry-Perot etalon with thicknesses of d₁=1.6mm and d₂=10mm is inserted into the cavity with optical length L=300mm,and the tilt angle is 0.5°and 0.9°,respectively.When the delay time is 180μs,a single longitudinal mode operation is obtained at a repetition frequency of 10Hz,and the selection success rate is close to 100%.The output beam has a single pulse energy of 1.03mJ and a pulse width of 13.2 ns,4 hours energy stability is better than 3%.After a two-stage amplifier,the final output energy is 492.8mJ.Experiments show that this combination is a stable and reliable method to achieve single longitudinal mode seed source.