Suppression of excited-state absorption: A path to ultraviolet tunable solid-state lasers

A method of suppression of losses due to excited-state absorption (ESA) in laser crystals is proposed, based on the well-known phenomenon of electromagnetically induced transparency. Typical situations in which ESA prevents lasing are considered. Theoretical analysis shows that by using an additional driving laser field one can inhibit ESA and make lasing possible. On the basis of available spectroscopic information estimates for rare-earth-ion-doped laser materials are presented. They show the feasibility of obtaining optical gain at parity-allowed 4fⁿ↔4f^n-15d transitions of rare-earth ions in the ultraviolet spectral region after suppression of ESA at an emission wavelength into the conduction band of a host material.