Fluorescence quantum efficiency of Ti3+:Al2O3 at cryogenic temperatures and excitation by laser diodes

Abstract

Abstract In this work the temperature dependences of the fluorescence of a titanium-sapphire crystal excited by radiation with λ=507 nm, λ=454 nm and λ=405 nm are measured. The quantum efficiency of fluorescence is determined. It was found for the first time that the quantum efficiency of fluorescence exceeds 100% in the cryogenic temperature range when the crystal is excited by radiation with λ = 454 nm. It is equal to (117 ± 5) % and (114 ± 5) % at T = 77 K for crystals grown by the Czochralski method and by gradient of temperature one, respectively.