Research On Passively Q-switched All-solid-state Lasers From Nanomaterials

Because passive Q-switched laser does not need an additional electronic Q-switch,only by putting a saturable absorber?SA?into the resonator of the laser,it can realize the output of pulse laser depending on its saturable absorption characteristics of specific wavelength light.Because of its high cost performance and easy operation,it has attracted the attention of researchers.In recent years,nano materials with saturated absorption properties have gradually become one of the factors to promote the development of laser pulses.As a new type of saturable absorber,gold nanomaterials are becoming more and more perfect with the further study of the preparation process.It not only has the future trend of Q-switching in a wide wavelength range,but also can show different optical properties by adjusting the proportion of different shape lengths of gold nanomaterials.Due to the influence of local surface plasmon resonance?SPR?excitation,gold nanostar has the characteristics of large third-order nonlinearity,broadband absorption and fast response time,which enables it to reach picosecond level in recovery time and speed,making it an excellent visible light saturable absorber.The characteristics of gold nano star also show that it has great space for exploration and development in the future,especially in laser applications.In this paper,gold nanostar is used as saturable absorber in passive Q-switched laser,Nd:YAG crystal is used as gain medium,and 808 nm LD is used as the pump source,1064 nm Q-switched laser is obtained.It is also proved that the gold nano star material can be used as a saturable absorber for 1064nm all solid state laser,which provides references for further research on the saturable absorber of gold nanostar material.The main contents of this paper are as follows:1.This paper focuses on the research on the working principle and application field of all solid state laser,focusing on the related passive Q-switching technology,and also describes the basic principle of Q-switching technology and the resonator.2.Several kinds of laser crystals were mainly introduced.The working characteristics of Nd:YAG crystal,Nd:YVO₄ crystal and Yb:YAG crystal were introduced.The basic properties and parameters of several different crystals were also described.3.Several kinds of SA were introduced systematically,including traditional SAs:Cr^4:YAG crystal,semiconductor saturable absorption mirror,and some novel SAs:graphene,carbon nanotubes?CNT?.4.In this paper,gold nano materials were introduced comprehensively.The gold nanostar with the size of 40-45 nm was mainly used as SA.The characteristics of the output laser of the Nd:YAG laser are analyzed.The 1064 nm passively Q-switched laser operation with the maximum average output power of 97 mW and the minimum pulse width of 204 ns was realized.