Investigations On 447nm Blue Laser Technology

Diode pumped all-solid-state blue laser(blue DPL) sum up the advantages of DPL which are stable function,compactness,high efficiency and long lifetime,and the advantages of blue laser which are short wavelength,high photon energy,far transmission distance under the water and eye-sensitive.So it is widely used in optical data storage,laser color display,underwater communication,biomedical etc.At present,the method of laser diode(LD) end-pumped working and using nonlinear crystal frequency doubling to obtain blue laser has been widely used.However,it has limitations in improving blue laser output power and obtaining new wavelength.Therefore,this paper presents a new method to obtain blue laser through Nd³⁺ 1.3μm spectral line of third harmonic generation(THG).Based on this method,a new wavelength of 447nm blue laser using the intracavity THG in 1341.4nm high power LD arrays(LDA) side-pumped CW Nd:YAP was obtained in the experiment. The main theoretical and experimental research contents were completed as follows:(1) According to the absorption characteristics of Nd:YAP crystal and the luminescence characteristics of LD bars,the theory of Gaussian beam ray trace was combined with a parameter that was quantificationally evaluates of the absorbed pump light distribution.The unique structure of LDA off-axis staggered pumped was designed.The high efficiency and uniform absorption of pump light was obtained.(2) On the basis of resonant three wave coupling equations of sum frequency and phase-matching conditions,conversion efficiency equations of sum frequency were combined.KTP matching parameters,optimal photon number ratio and optimal crystal length were simulated in the process of sum frequency.(3) According to the equation of steady state heat conduction,the methods of finite element analysis and finite difference were used for quantitative analysis of laser crystal and nonlinear crystal under the condition of circulating water cooling.The cavity structure parameters were optimally designed by the resonator theory of G parameter and ABCD transfer matrix of Gaussian beam.(4) Based on the theory analysis of unit technology,experimental research was carrying on.A maximum output power 103mW of 447nm CW blue laser was obtained.And the beam quality M² value equaled 12.23 and 12.57 in both horizontal and vertical,respectively.