Study On 1.3 ?m Pulse Laser Based On Fe₃O₄ Nanoparticles Saturable Absorber

All solid-state pulse laser based on saturable absorber has been widely studied and used because of its simple structure,low cost and easy operation.As a new type of saturable absorber,Fe₃O₄ nanoparticles?FONP?have attracted much attention due to its semiconductor characteristics,large third-order nonlinear polarizability,adjustable band gap width and ultra-wide working bandwidth.In this paper,the application of FONP in1.3?m all-solid-state laser is studied.The pulse output is realized in 1.3?m all-solid-state Nd:YVO₄ laser by using the self-made FONP saturable absorber.The performance of the laser is improved by using the improved saturable absorber.The main contents of this paper are as follows:Firstly,the properties of magnetic fluid,a new functional material composed of FONP,are studied.The linear optical properties of magnetic fluid are studied.The saturable absorption principle of FONP is analyzed theoretically;different types of saturable absorbers based on FONP and GO are studied and prepared;the experimental FONP and GO are tested and characterized,and the nonlinear optical properties of three kinds of self-made saturable absorbers are tested and characterized.Secondly,a 1.3?m all-solid-state passively Q-switched laser based on FONP is studied.All kinds of parameters of the laser are designed.For the first time,the 1.3?m Q-switched pulse laser output based on the FONP saturable absorber is realized,with a pulse width of 654 ns,a repetition frequency of 147 k Hz and an output power of 151 m W.The all-solid-state Q-switched pulse laser output based on the FONP and the GO-FONP is realized,with a pulse width of 163 ns,a repetition frequency of 314 k Hz and an output power of 306 m W.Thirdly,a 1.3?m all solid-state passively Q-switched mode-locked laser based on FONP is studied.The output of Q-switched mode-locked pulse based on FONP saturable absorber is realized for the first time.The average output power is 157 m W,the minimum pulse width of Q-switched envelope is 767 ns,the repetition frequency is 116 k Hz,the minimum pulse width of the mode-locked pulse is 660 ps,and the repetition frequency is154.5 MHz.