Xihe Zhang

All-solid-state cw frequency-doubling Nd:YLiF4/LBO blue laser with 4.33 W output power at 454 nm under in-band diode pumping at 880 nm

We generated efficient blue laser output at 454 nm by intracavity frequency doubling of a continuous-wave (cw) diode-pumped Nd:YLiF(4) (Nd:YLF) laser at 908 nm based on the (4)F(3/2)-(4)I(9/2) transition. With 32.8 W of incident pump power at 880 nm and the frequency-doubling crystal LiB(3)O(5), a level as high as 4.33 W of cw output power at 454 nm is achieved, corresponding to an optical conversion efficiency of 13.2% with respect to the incident pump power. To the best of our knowledge, this is the first blue laser at 454 nm generated by intracavity frequency doubling of a diode-pumped Nd:YLF.

Research on the hollow double-half Gaussian laser beams of long distance detection source

In this paper, a new kind of long distance detection source-- hollow double-half Gaussian laser beams is put forward. By use of modified Cassegrain optics system, we obtained hollow beams with special light distribution-parallel hollow double-half Gaussian laser beams, the intensity distribution of this kind of hollow beams is zero at all the hollow area and is maximum at inner margin, so forms double half-Gaussian beams, and the inner and the outer diameters of the hollow beams are controllable. The analytical equation of propagation and transformation of the hollow laser beams in free space was deduced. The simulation shows that the intensity exhibits three-dimensional trap distribution in the near-field, while the double half-Gaussian hollow beams turns into solid laser beams when propagating a certain distance, which shows the characteristic of self-focus. By use of the characteristic of self-focus of the double half-Gaussian hollow beams, we can realized the self-gating long distance detection to the small object even if in the condition of lower laser power. The technology will be applied broadly in the near years.