Abstract

One of the interests in solid-state laser physics has focused on diode-pumped blue and green upconversion lasers. At 551 nm upconversion-pumped laser operation in Er³⁺:LiYF₄ at cryogenic temperatures has been reported, see e.g., Ref. ¹. Recently room-temperature lasing under different excitation schemes has been achieved.^2,3 However, the population and deexcitation processes of the upper laser level as well as the influence of reabsorption on the laser wavelength⁴ have not yet been quantitatively understood. In this paper the results of a computer simulation of the Er³⁺:LiYF₄ laser are reported. The rate-equation scheme considers all excited levels up to ²H_9/2, ground-state depletion, excited-state absorption (ESA) on the pump and laser wavelength, three upconversion processes, stimulated emission, and a realistic resonator design. From the computer simulation the population mechanisms of the laser system are analyzed and suggestions for a better laser performance are derived.

© 1994 IEEE