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Pulse-LD Intermittent Pumped Tm:YAG 2?m Acousto-optic Q-switched Laser

Posted on:2018-05-06Degree:MasterType:Thesis
Country:ChinaCandidate:N LiuFull Text:PDF
GTID:2348330533467388Subject:Physics, optic
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Laser-diode-pumped thulium-doped solid-state lasers are important ways to obtain 2?m-band lasers,which have been shown to be indispensable in many applications.In this thesis,the pulse-pumped Tm:YAG 2?m acousto-optic Q-switched lasers are studied in theory and experiment.The main research contents are as follows:In theory,based on the energy level transition of Tm3+,rate equation was established and solved for pulse pumped Tm3+Q-switched laser.Laser output characteristics was calculated in theory.Inner heat distribution of Tm:YAG crystal was simulated by COMSOL software.At the same time,heat conduction equation was solved by integral transformation and thermal focal length of Tm:YAG crystal was simulated by MATLAB.Two intermission pumped resonator were designed with the consideration of thermal focal length,which provides theory for experimental research.Firstly,measurement experiments of thermal focal length of pulse LD pumped Tm:YAG was carried out.In single-end pumping situation,at repetition frequency of 100 Hz,thermal focal length fall from 768 mm to 269 mm with injecting energy 14.5-130.2mJ;At repetition frequency of 200 Hz,thermal focal length fall from 968 mm to 124 mm with injecting energy 14.5-160 mJ.In double-end pumping situation,at repetition frequency of 100 Hz,thermal focal length fall from 535 mm to 126 mm with injecting energy 14.5-130.2mJ;At repetition frequency of 200 Hz,thermal focal length fall from 450 mm to 75 mm with injecting energy 14.5-160 mJ.Secondly,the experimental study of pulse LD intermittently pumped single dual-rod-bonding Tm:YAG acousto-optic Q-switched laser was done.At the repetition frequency of 200 Hz,5.41 mJ of output energy of 2013.94 nm was obtained with pumped power of 118 mJ,pulse width of 395.4ns and slope efficiency of 12.79%,and the beam quality is 1.49 in x direction and 1.59 in y direction.After it,the experimental study of pulse LD intermittent pumped single-end bonding Tm:YAG two rods series connection acousto-optic Q-switched laser was worked.When the repetition frequency of pumped power of single crystal is 100 Hz and repetition frequency of Q-switching is 200 Hz,the output energy of 2014.22 nm is 6.04 mJ with pumped energy of 176 mJ,corresponding to the slope efficiency of 13.06% and the pulse width of 377.9ns,and the beam quality is 1.29 in x direction and 1.45 in y direction.The results show that the intermittent pump technique has the effect of increasing the output energy and doubling the repetition rate.Finally,changing the frequency conditions and the pump method was tested for comparation.The results show that the operation repetition frequency of the intermittent pump laser is closely related to the lifetime of the laser material.
Keywords/Search Tags:Intermittent pumping, Tm:YAG, 2?m laser, Acousto-optic Q-switching
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