Mid-IR Microchip Laser: ZnS:Cr2+ Laser with Saturable Absorber Material

Abstract

A method of fabrication of laser gain material and utilization of such media includes the steps of introducing a transitional metal, preferably Cr 2+ thin film of controllable thickness on the ZnS crystal facets after crystal growth by means of pulse laser deposition or plasma sputtering, thermal annealing of the crystals for effective thermal diffusion of the dopant into the crystal volume with a temperature and exposition time providing the highest concentration of the dopant in the volume without degrading laser performance due to scattering and concentration quenching, and formation of a microchip laser either by means of direct deposition of mirrors on flat and parallel polished facets of a thin Cr:ZnS wafer or by relying on the internal reflectance of such facets. The gain material is susceptible to utilization of direct diode or fiber laser pumping of a microchip laser with a level of power density providing formation of positive lens and corresponding cavity stabilization as well as threshold population inversion in the laser material. Multiple applications of the laser material are contemplated in the invention.

1 . A method for constructing and using a transition metal doped laser media comprising the steps of:
 a. forming a crystal of a thickness sufficient for use as a microchip lasing material, where the crystal is selected from the structures of MeZ and MeX 2 Z 4 , wherein Me is selected from the group consisting of Zn, Cd, Ca, Mg, Sr, Ba, Hg, and Pb; Z is selected from the group consisting of S, Se, Te, O and their mixtures; and X being selected from the group consisting of Ga, In, and Al;   b. depositing a thin film layer of a transition metal on opposing faces of said crystal by a method selected from the group of pulsed laser deposition, cathode arc deposition, and plasma sputtering;   c. annealing said crystal in an oven for a period and at a temperature sufficient to allow crystal doping by transition metal diffusion and replacement in selected regions of said crystal.   
   
   
       2 .- 34 . (canceled)