Open AccessTemperature-dependent radiative lifetime of Yb:YLF: refined cross sections and potential for laser cooling
Author(s) -
Stefan Püschel,
Sascha Kalusniak,
Christian Kränkel,
Hiroki Tanaka
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.422535
Subject(s) - materials science , ytterbium , radiative transfer , laser , spectroscopy , erbium , laser cooling , excited state , ion , optics , atomic physics , crystal (programming language) , chemistry , physics , organic chemistry , quantum mechanics , computer science , programming language
We revisit the spectroscopic characterization of ytterbium-doped LiYF 4 (Yb:YLF) for the application of laser cooling. Time-dependent fluorescence spectroscopy reveals a temperature dependence of the radiative lifetime which we explain by the Boltzmann distribution of excited ions in the upper Stark levels. The emission cross sections of Yb:YLF from 17 K to 440 K are revised using the temperature-dependent radiative lifetimes from fluorescence spectra. We provide fit equations for the peak values of important transitions as a function of temperature, which is also useful for the design of Yb:YLF laser oscillators and amplifiers operated at cryogenic temperatures. Based on our spectroscopic data, we show the prerequisite crystal purity to achieve laser cooling below liquid nitrogen temperatures.