Scaling of energy characteristics of polycrystalline Fe²⁺:ZnSe laser at room temperature

The lasing characteristics of lasers based on diffusiondoped Fe²⁺:ZnSe polycrystalline samples excited at room temperature by an electric-discharge HF laser are studied. A sample doped from two sides (working surfaces) emitted laser radiation with the energy E='253' mJ with the slope efficiency η_d = 33% and the efficiency with respect to the absorbed energy η_abs ≈ 28% in the case of an elliptical pump spot of size a × b = 6.8 × 7.5 mm. It is found that the possibility of increasing the lasing energy of the samples of these types by increasing the pump spot area (at a constant pump energy density) is limited by the appearance of parasitic generation typical for disk lasers. The first results are reported on the laser based on a polycrystalline sample made by a technology that allows one to form a zero dopant concentration on the surface and a maximum concentration inside the sample (i.e., to create a sample with internal doping). The possibilities of increasing the Fe²⁺:ZnSe laser energy at room temperature by using multilayer samples fabricated by this doping method are discussed. (lasers)