Population mechanisms of the roomtemperature 551 nm Er:LiYF4 laser

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 2H9/2, 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.