A method for constructing and using a transition metal doped laser medium 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 MeX 2 Z 4 and MeZ, 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 doping of the transition metal ions inside said crystal by transition metal diffusion and replacement in selected regions of said crystal, the doped crystal operable to absorb pump light at a pump wavelength to produce a laser gain at a laser wavelength different from the pump wavelength, characterised by further comprising: establishing an electrical field across said crystal and between transition metal thin films on the opposing surfaces of said crystal during said annealing step to promote said transition metal diffusion and subsequent to said annealing step, depositing two dichroic mirrors directly on two opposing faces of said crystal, respectively, wherein the two dichroic mirrors are configured to reflect light at the laser wavelength in such a way as to form a laser cavity between the two dichroic mirrors and to transmit light at the pump wavelength to effectuate optical absorption inside said crystal to cause a positive lens effect inside said crystal to stabilise the laser cavity. a. forming a crystal of a thickness sufficient for use as a microchip lasing material, where the crystal is selected from the structures of MeX 2 Z 4 and MeZ, 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 doping of the transition metal ions inside said crystal by transition metal diffusion and replacement in selected regions of said crystal, the doped crystal operable to absorb pump light at a pump wavelength to produce a laser gain at a laser wavelength different from the pump wavelength, characterised by further comprising: establishing an electrical field across said crystal and between transition metal thin films on the opposing surfaces of said crystal during said annealing step to promote said transition metal diffusion and subsequent to said annealing step, depositing two dichroic mirrors directly on two opposing faces of said crystal, respectively, wherein the two dichroic mirrors are configured to reflect light at the laser wavelength in such a way as to form a laser cavity between the two dichroic mirrors and to transmit light at the pump wavelength to effectuate optical absorption inside said crystal to cause a positive lens effect inside said crystal to stabilise the laser cavity.