Total internal reflection-based side-pumping configuration for terawatt ultraviolet amplifier and laser oscillator development

Abstract

A two-side-pumping scheme that is based on total internal reflection in a diamond-cut Ce³⁺:LiCaAlF₆ crystal suitable for the development of an ultraviolet laser and femtosecond amplifier system is proposed. Experimental fluorescence images and lasing results that demonstrate total internal reflection of the excitation beam using this diamond-cut crystal are presented. Calculations for the optimized crystal geometry that facilitate high extraction efficiency and homogeneity of the absorbed excitation beam are also discussed. About 50% increase in extraction efficiency compared to previously reported chirped-pulse femtosecond ultraviolet amplifier operating at 50-GW peak power is expected using this total internal reflection-based two-side-pumping configuration and a diamond-cut Ce³⁺:LiCaAlF₆ crystal with a geometry of ${\phi _1}$ = 103°, ${\phi _2}$ = ${\phi _4}$ = 82°, ${\phi _3}$ = 93°, a length of 1.23 cm, a height of 2 cm, and an absorption coefficient of ~ 1.5 cm⁻¹. Our results can be used as a guide during the crystal growth process by providing the appropriate crystal geometry and size for a particular absorption coefficient to achieve high extraction efficiency. With the appropriate crystal combined with multiple-beam pumping afforded by the side-pumping scheme, the development of an all-solid-state ultraviolet laser operating at terawatt level would be within reach.