Eyesafe laser system using transition metal-doped group ii-vi

Abstract

An eyesafe laser system includes a Q-switch crystal formed of a semiconductor host material having noncentrosymmetric tetrahedral substitutional sites doped with transition metal ions in concentrations from about 0.001 to about 0.10 atomic percent, which functions as to be a saturable absorber of light at eyesafe wavelengths with a relatively long relaxation lifetime. Co.sup.2+ :ZnSe has been demonstrated to have advantageously high absorption cross section and advantageously high relaxation lifetime at both 1.54 .mu.m (Er:glass laser) and 1.6 .mu.m (Er:YAG laser). Other candidate host materials include other zinc chalcogenides, cadmium chalcogenides and zinc oxide. The resultant Q-switch does not require additional focusing optics inside the cavity and has a saturation fluence which is approximately one order of magnitude less than other state of the art saturable absorbers in the 'eyesafe' wavelength region, thereby permitting substantially faster Q-switch bleaching, lower thermal loads, and less potential for damage than was hitherto possible.