A Dual-Wavelength Diode-End-Pumped Nd:YVO₄ Electro-Optical Q-Switched Laser

The 1064/1342nm dual-wavelength laser has the characteristics of low fiber loss,strong absorption in water and atmospheric transmission window.It has unique application prospects in laser ranging,laser guidance,coherent communication,atmospheric research,optical image processing etc.The 593nm laser beam produced by the sum frequency belongs to the yellow band,which can be used as beacon light to measure the distortion of the laser in atmospheric transmission.In addition,Nd:YVO₄ crystal has the advantages of low threshold and high efficiency,and is an excellent working substance for generating1064/1342nm laser.At present,the research on dual-wavelength electro-optical Q-switched lasers mainly focuses on the three-cavity structure using a electro-optical Q-switched crystal,and few double Q-switched crystals are used.In this thesis,the Nd:YVO₄1064/1342nm dual-wavelength dual-electro-optic Q-switched laser with reasonable output power ratio and good time-overlap of output pulse is studied theoretically and experimentally.?1?According to the dual-wavelength Q-switching theory,the LD end-pumped Nd:YVO₄ 1064/1342nm dual-wavelength Q-switched laser rate equation is listed,and the electro-optical Q-switching loss correction term is added.The analysis of the rate equation gives the best output mirror transmittance.through the Matlab simulation software to solve the rate equation using the Runge-Kutta method,the effect of dual-wavelength cavity length and electro-optic crystal Q-switched pressure on the output ratio of dual-wavelength pulsed laser output is obtained.At the same time,get the relationship between the double-electro-optical Q-switched Q-switch open-gate delay and the simultaneous output of dual-wavelength.?2?Getting the focal length of the crystal thermal lens at a certain pump power by solving the heat conduction equation of Nd:YVO₄ crystal,analyzing the physicochemical properties of the electro-optic crystal,calculating the Q-switched?V₂voltage of different wavelengths.And design a new resonant cavity structure that uses a single working substance,double electro-optical Q-switched crystal to Q-switch 1064nm and 1342nm laser respectively.Calculate the stability map using the ABCD matrix.Finally,the 1342nm output mirror transmittance is 3%,and the cavity length is 70mm,the 1064nm output mirror transmittance is 40%,and the cavity length is 160mm,and using RTP electro-optic Q switches for dual-wavelength electro-optic Q-switched laser output.?3?Based on the theoretical and experimental design,the output characteristics of the Nd:YVO₄ 1064/1342nm dual-wavelength continuous laser and the output characteristics of the dual-wavelength dual-electron crystal Q-switched laser were experimentally studied.The output mirror transmittance at 1342nm was obtained.It is 3%,the cavity length is70mm,the 1064nm output mirror transmittance is 40%,the cavity length is 160mm,the repetitive frequency is 10kHz,the pumping power is 33.1W,the 1342nm electro-optic Q-switched crystal voltage is 2250V,and the 1064nm electro-optical Q-switched crystal voltage is 1690V,Based on the 1342nm Q switch trigger time,1064nm electro-optic Q-switch delays 1300ns,the output power of 1064nm and 1342nm is 0.45W/0.404W.The pulse width is 38.15ns/63.14ns,respectively,and the output pulse peak time overlaps the1064/1342nm double pulse laser.