Research On Passive Q-switched Laser Based On Ti₃C₂T_x

Passive Q-switched laser has the advantages of high pulse output energy and peak power,low debugging difficulty,high efficiency and compact structure.It has a wide application prospect in biomedicine,lidar and laser display fields.The new two-dimensional material MXene has good optical properties and tunability.The purpose of this project is to study the adaptability of Ti₃C₂T_x2D material as a Q-switched device in passive Q-switched lasers.By changing the concentration of saturable absorber,the length of resonator and the transmittance of output mirror,the change rule of average power,repetition frequency and pulse width of Ti₃C₂T_xpassive Q-switched laser is explored.The details are as follows:Theoretically,the optical properties of Ti₃C₂T_xare described,especially the saturable absorption characteristics are analyzed in detail.The band structure diagram and state density of Ti₃C₂T_xwith different functional groups were simulated by Material Studio,which further revealed the advantages of this material in the field of optical application.Based on the Q-switching process of Nd:YAG passive Q-switched laser,the influence factors of the output characteristics of Q-switched pulse are analyzed by using Matlab software.It provides a theoretical basis for the subsequent application of Ti₃C₂T_xas a saturable absorber in passive Q-switched lasers.Experimentally,the Ti₃C₂T_xpassive Q-switched laser is studied by changing the cavity length of the resonator.In the experiment,a semiconductor laser was used as the pump source and a linear resonator structure,and Ti₃C₂T_xwith a concentration of 0.02 mg/ml was configured as the saturable absorber.The cavity lengths of the resonators were 63mm and75mm respectively.It is found that the shorter the cavity length of the resonator is,the higher the repetition frequency is and the narrower the pulse width is.When the cavity length is 63mm and the pump power is 8.822W,the average output power is 0.224W,the repetition rate is 131.4KHz,and the narrowest pulse width is 1.833μs.When the cavity length is 75mm,the pump power is 8.822W,the average output power is 0.218W,the repetition rate is 124.6KHz,and the narrowest pulse width is 3.703μs.The results show that Ti₃C₂T_xhas saturable absorption characteristics.And it is an effective way to increase repetition frequency and shorten pulse width to reduce cavity length in Q-switched laser.Secondly,0.02mg/ml,0.03mg/ml,0.04mg/ml,0.05mg/ml Ti₃C₂T_xdispersions were prepared respectively,and they were put into the resonant cavity to realize the pulse light output of Q-switched laser.It was found that the higher the concentration of Ti₃C₂T_xdispersion,the higher the average output power,the higher the repetition frequency and the narrower the pulse width.When the pump power is 8.822W,the maximum average output power is 0.215W,the repetition rate is 139.4KHz,and the narrowest pulse width is 480ns when the pump power is 8.822W with 0.05mg/ml solution.Finally,the passive Q-switched laser pulse output is achieved by using output mirrors with transmittance of 10%and 20%respectively.The experimental results show that when the transmittance of the output mirror is 10%,the average output power of the output laser is higher,the pulse width is narrower and the repetition frequency is higher.When the pump power is 7.094W,the average output power is 0.292W,the repetition rate is 117.2 KHz,and the narrowest pulse width is 1.422μs.The experimental results are in agreement with the theoretical simulation.The results show that Ti₃C₂T_xhas good saturable absorption characteristics and is suitable for Q-switched lasers,and has a broad application prospect.