High Energy Diode-side-pumped Q-switched Nd:YAG Solid-state Laser With A Thermoelectric Cooler

With the breakthrough of the LD technology,solid-state lasers have been strongly developed and the application areas of solid-state lasers have been expand.One of the most important development is the LD pumped solid-state laser,which is a high efficiency,long life,high beam quality,good stability,compactly and new type of solid-state lasers.Especially the Q-switched solid-state lasers,has become a hot topic of international researches.The solid-state lasers without water-cooling which is more compact,making it an effective means of miniaturized and portable lasers.A diode-side-pumped,high-energy and short pulse duration solid-state Nd:YAG laser with a thermoelectric cooler is investigated in this dissertation,which has some reference significance for domestic and foreign researchers.The study includes follow parts:1?We derived the formula between the output energy,the pulse width,the optimal output mirror coupling transmittance and the dimensionless variable function z by analyzing the rate equation.And the output energy and pulse width of the laser are estimated.Then,through the stability analysis of the resonant cavity,the position relation of the cavity mirror is determined.2?The oscillator operated in free oscillation and Q-switched.And the parameters of the resonator were optimized.The polarization transmittance characteristics of the polarizer,the output mirror transmittance,the cavity length,the LD pump pulse width,the TEC temperature control accuracy and the cooling temperature on the output were tested respectively.The transmittance of polarizing plate was Tp=99.52%and Ts=0.123%.The pump laser was a pulsed laser diode array with maximum peak power of15 kW.The dimension of the Nd:YAG crystal rod was?7mm×100 mm and the doping concentration was 1.1±0.1 at%.The transmittance of output mirror was 75%.The cavity length was 280mm and the TEC temperature control accuracy was 0.01?.The cooling temperature was 25?.The LD pump pulse width was 200?s,repetition rate was 10Hz and pump current was 80A.And finally a 350 mJ laser pulse was obtained with a pulse duration of 9.7 ns,a wavelength of 1064 nm and a beam quality M~2 of 7.7and 12.3 for horizontal and vertical directions,respectively.The output stability was2%,the optical-to-optical conversion efficiency and the electro-optical conversion efficiency were 13.3%and 6.7%,respectively.3?We studied the characteristic of the amplifier.The dimension of the Nd:YAG crystal rod used in first amplifier was?7.5mm×134 mm and the doping concentration was 1.1±0.1 at%.The first amplifier was pumped by a pulsed laser diode array with maximum peak power of 24 kW.A 700mJ,10ns laser pulse was obtained when the first amplifier operating parameters was 90A,200?s,10Hz.The dimension of the Nd:YAG crystal rod used in second amplifier was?8mm×134 mm and the doping concentration was 1.0±0.1 at%.The second amplifier was pumped by a pulsed laser diode array with maximum peak power of 24 kW.A 1035mJ,9.9ns laser pulse was obtained when the second amplifier operating parameters was 80A,200?s,10Hz.