In this paper

a kind of new structure of all solid-state SHG blue laser with an external resonant cavity containing a nonlinear crystal is presented.Laser diode at 860nm is used as a fundamental frequency laser source and nonlinear crystal KTP is used for the frequency doubler.The optical isolator is comprised of a polarizer and a waveplate at λ/4.The half confocal resonator consists of one of end planes of the polarzer and spherical mirror.Stable operation of blue laser of output power of 2mW at 430nm can be obtained

and the distribution of SHG laser intensity is a Gaussian beam.