The Research Of All-Solid-State Composite Cavity Cyan Laser With Intracavity Sum-frequency Mixing

All-solid-state lasers are widely used in military,civil and commercial fields because of their portable,simple structure and high beam quality.Due to the limitation of crystal transition spectra,It is difficult to obtain blue-green laser output between 470 nm and 510 nm directly.It can only be obtained by non-linear frequency transformation,but these special bands have special applications in some fields.Because the absorption loss of seawater is small,and it has strong penetration and good directivity in seawater.Among the blue and green wavelength range,lines around 500 nm which can be called cyan is offen used for underwater communications,bathymetry and so on.It also have special applications in biomedical field.However,the cyan laser conditions required in different seawater environments are different,so how to obtain efficient cyan laser is of great significance.In the past,most of the reports about cyan laser are based on experiments,but relatively few on theoretical research.Therefore,this paper will study how to obtain efficient cyan laser from the following aspects..(1)Based on the theory of lasers,the operation characteristics of quasi-three-level lasers and four-level lasers are analyzed,A mathematical model of two-cavity independent oscillation laser is established.According to the model,the parametric relationship describing the operation characteristics of laser is obtained,and its variation under different conditions is simulated.Combining with the nonlinear optical coupled wave equation,the factors affecting the frequency efficiency are analyzed,and the factors that can be used to improve the sum frequency efficiency in the experiment are determined.(2)Design and optimize the overall structure and related components of all-solid-state intracavity and frequency cyan laser.The final cavity type is determined,and the relevant values are simulated and analyzed by using MATLAB software.The parameters of input mirror curvature and cavity length are determined.And then,the relative parameters and placement of crystal LBO for sum frequency are determined by comparing and analyzing with SNLO software.(3)Based on the previous theoretical analysis and related simulation parameters,experimental research is carried out on the designed experimental structure.The independent oscillation output of 946 nm quasi-three-level laser and 1064 nm four-level laser are obtained respectively.The common output of 946 nm and 1064 nm and the continuous output of intracavity sum-frequency 501 nm cyan on this basisc are realized.The problems in the experiment are also analyzed.