Study On Pulsed Laser Properties Of Several New Crystals

Pulsed laser is openly available in photo-communication,materials processing,medical laser,ultrafast laser spectroscopy and military fields,which is because that the pulsed laser has a narrow pulse width,high peak power and wide spectrum.As the core component of laser,the choice of gain material is very important.Up to now,hundreds of neodymium and ytterbium doped laser crystals have been successfully realized short pulse laser output.Therefore,people urgently begin to explore new crystals,which has become a hot field of laser technology study.As the most important means to generate short pulse laser,passive Q-switching and mode-locking techniques are popular because of their simple operation and low cost.The development of laser crystals and saturable absorbers,which are important components for generating short pulses,has attracted much attention.In this paper,the pulse laser properties of Yb:LuYAG,Nd:GSAG and Yb:CALGO crystals were studied by using MoS₂,gold nanoparticles and SESAM as SA.The main work is summarized as follows:1.Using MoS₂ and gold nanoparticles as saturable absorbers,we studied the optical properties of Yb:LuYAG laser in passively Q-switched operation.In the experiment,we found that the output power,pulse width and repetition frequency varied with the pump power,we studied the relationship between them.During continuous-wave laser operation,the Yb:LuYAG crystal has achieved dual-wavelength output,with the output wavelength of 1029.41 nm and 1047.16 nm.The saturable absorber of MoS₂ was successfully prepared by liquid-phase stripping method.Then we realized an operation of passively Q-switched,which was based on the prepared MoS₂ saturable absorber.We recorded the experimental data and found that the output pulse with pulse width of 293ns was successfully obtained.At this point,the absorption pump power was 3.39 W,and the dynamometer indicates that the output power was 0.144 W.In addition,the saturable absorber of gold nanoparticles was successfully prepared by sodium citrate reduction method;based on gold nanoparticles saturable absorber,passively Q-switched operation was realized in the Yb:LuYAG laser.The laser properties of two kinds of saturable absorbers made of gold nanoparticles with different concentrations in Yb:LuYAG laser were studied.It was found that the saturable absorber made of gold nanoparticles with larger concentration has shorter pulse width.When the pump power was 3.9 W,the shortest pulse width was 104 ns.2.In Nd:GSAG laser,the optical properties of continuous-wave operation were studied.Besides,the passive Q-switching operation were realized and its optical properties were studied.During continuous-wave laser operation,the Nd:GSAG crystal realized dual-wavelength output,and the output wavelengths were 1060.24 nm and1062.4 nm,respectively.The MoS₂ saturable absorber was prepared by liquid phase stripping method.Inserting the prepared saturable absorber,when the Nd:GSAG laser has a stable output.Then we realized passively Q-switched operation,and obtained the output pulse with pulse width of 571.9 ns.At this point,the maximum output power was41.3 m W.3.Using Kerr-lens mode-locking technology,the pulses properties of the self-mode-locked operation of Yb:CALGO laser were studied.The shortest pulse width was 42 fs.In addition,using Semiconductor Saturable Absorber Mirror（SESAM）mode-locking technology,the pulses properties of the SESAM mode-locked operation of Yb:CALGO laser were studied.The shortest pulse width was 78 fs.