Research On LED Side Pumped Q-switched Green Laser

The development and application of solid-state laser technology has not only greatly contributed to academic progress,but is also widely used in people’s daily lives and in agriculture,medicine and the military,and still has an irreplaceable role to play.The pump source of solid-state lasers has undergone a succession of changes from flash lamps,light emitting diode（LED）to laser diode（LD）.The LED emission spectrum is usually in the range of 20-60 nm,which is wider than LD,but much narrower than flash,and can usually cover multiple absorption peaks in the laser material.With the low cost and miniaturisation of LED in recent years and the substantial increase in power,this moderate broadband pumping from LED is expected to become a commercial low-cost laser of choice,with long life,simple system structure,stable operation and high conversion efficiency.This paper focuses on the output characteristics of an all-solid-state green laser with LED as the pump source,and builds all-solid-state lasers with Nd:YAG and Nd:YLF crystals as the gain medium by means of side pumping,respectively,as follows:1.Introduces the theory fundamentals of LED side-pumped all-solid-state green lasers,mainly covering the principles and techniques of Q-switch,the selection and basic parameters of experimental equipment and the luminescence characteristics of LEDs.2.Comparison of the 1064 nm fundamental frequency light output characteristics of LED-pumped Nd:YAG lasers with different doping concentrations and selection of the best experimental solution for 1064 nm fundamental frequency laser.Finally,a maximum average power output of 10.3 W is achieved at a repetition frequency of 100 Hz,with a maximum single pulse energy of over 100 m J,corresponding to the highest optical-optical conversion efficiency of 25.4%and slope efficiency of31.3%.3.The acousto-optical Q-switch frequency doubling device is built on the basis of the 1064 nm fundamental frequency laser maximum power output module,and by optimising the incidence angle of the KTP crystal to meet the non-critical phase matching condition,3.8 W average power of 532nm green laser is generated at a repetition frequency of 10 k Hz,corresponding to a maximum frequency doubling conversion efficiency of 45.5%.4.Build an Nd:YLF laser system with an Nd³⁺doping concentration of 1.0at.%.The feasibility of LED-pumped Nd:YLF continuous lasers is verified by selecting suitable cavity parameters and shortening the cavity length.Next,the LED-pumped Nd:YLF solid-state laser with 1047/1053 nm dual wavelength output is achieved by fine-tuning the angle of the birefringent filter in the cavity.Finally,the study focuses on the output characteristics of the 1047 nm laser and realises the output of frequency doubling 523 nm green laser.