Several watts compact CW green laser head without cooling by using PPMgSLT

Abstract

Several watts compact CW green laser head without any cooling is demonstrated by combining CW fiber laser and PPMgSLT. Since the conventional high power visible laser has huge heat sources at its laser head, it requires air or water cooling. In addition, the optical system, which is mounted this type of head, has sometime problems of optical stability caused by those heat sources from the head. The laser head we demonstrated has three input and output ports of the laser light; fiber input of fundamental light (1064nm) from CW fiber laser, SHG (532 nm) output into free space, and fiber output of residual fundamental laser light. The size of laser head was 110mm X 78mm X 64mm (550cc). More than 25W of CW fundamental light from single mode fiber was focused into 30mm-long PPMgSLT device operated at 40 degree C. The linewidth of the laser was 0.09 nm at FWHM. 5W of 532 nm light was generated from PPMgSLT. Because of high power durability of PPMgSLT, it could be easily realized several watts of visible light generation by simple singlepass configuration. Residual fundamental light was separated by harmonic separator and was coupled into large core multi-mode fiber. As a result, there are no remarkable heat sources at the laser head. The stable green light from this head was confirmed without any cooling at the laser head. Since this configuration doesn’t affect any thermal turbulence in surroundings, the stability of the optical system would be improved by using this laser head.