Suppression of Transverse Parasitic Oscillation in Fe:ZnSe and Fe:ZnS Lasers Based on Polycrystalline Active Elements: A Review

The methods for suppressing transverse parasitic oscillation (TPO) at room temperature in Fe:ZnSe and Fe:ZnS lasers based on polycrystals doped using high-temperature diffusion have been considered. When active elements of this type are used, the development of TPO at large pump spots is due to the high dopant concentration on the surface of element end face and small length of the active medium as a whole (i.e., typical disk laser geometry). The TPO suppression methods under consideration are based on the fact that undoped Fe:ZnSe and Fe:ZnS exhibit significant absorption at the corresponding lasing wavelengths. Thus, the TPO development can be excluded by simple increase in the transverse size of active element and growth of active elements with several inner doped layers or an inner doped layer (layers) in the form of a meniscus. The problems of damage of active elements at large pump spots are discussed, and the potential of further increase in the radiation energy of Fe:ZnSe and Fe:ZnS lasers with room-temperature active elements is predicted.