Research On LD Pumped Passively Q-switched Er³⁺/Yb³⁺:glass Microchip Solid Laser Of 1kHz

LD pumped Er³⁺/Yb³⁺codoped phosphate glass passively Q-switched laser is one of the hot research topics in obtaining 1.5?m human eye safe band laser.The laser has the advantages of compact volume,simple structure,high conversion rate,low cost,easy product and the like,and can be widely applied to the fields of laser ranging,optical communication,medicine and the like.Therefore,it is very important for practical application to study and implement 1.5?m human eye safe band laser.In this paper,the research significance and application field of 1.5?m band laser are investigated and analyzed.At last,Er³⁺/Yb³⁺codoped phosphate glass is selected as the gain medium of the project.And determine the final research goals.A LD pumped kHz erbium ytterbium codoped phosphate glass passively Q-switched miniaturized laser is designed.The laser output with good stability is obtained through experiments.The main research contents and results are as follows:The energy level characteristics ofEr³⁺/Yb³⁺codoped phosphate glasses are analyzed in this paper.The energy level transition process ofEr³⁺/Yb³⁺codoped phosphate glass is complex,and the 1.5?m laser has co-upconversion,secondary energy transfer,excited state absorption and reabsorption at the same time.These processes will reduce pump efficiency and increase the thermal effect of the gain medium.In this paper,the thermal effect ofEr³⁺/Yb³⁺codoped phosphate glass is analyzed by COMSOL,and the thermal focal length is calculated.the effect of thermal lens effect on pattern matching is mainly studied,which can provide theoretical guidance for the selection of focal length of plastic lens.According to the rate equation,themainfactorscausingpulse instabilityareanalyzed theoretically.Base on that theoretical analysis,the effects of the focal length of the shape lens,the initial transmittance of Q crystal,the reflectivity of the output mirror a,the duty cycle of the pump source and the position of the pump beam waist in the gain medium on the single pulse energy and stability of the output pulse laser are studied experimentally.The LD pumped Er³⁺/Yb³⁺codoped phosphate glass passively Q-switched miniaturized 1535 nm laser has a repetition rate of 1kHz,a pulse width of 8ns,a single pulse energy of 35?J,an energy instability of 8.5%,a repetition frequency time instability of 9%and a beam quality M²=1.25.