Bonn 2000 – scientific programme

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Q: Quantenoptik

Q 40: Poster: Festkörperlaser

Q 40.7: Poster

Thursday, April 6, 2000, 16:30–19:30, Aula

Lasing and thermal properties of Er³⁺:Yb³⁺–doped fluoride phosphate glasses — •Jens Philipps¹, Thomas Töpfer¹, Joachim Hein¹, Roland Sauerbrey¹, H. Ebendorff-Heidepriem², and Doris Ehrt² — ¹Institut für Optik und Quantenelektronik, Universität Jena, Max-Wien-Platz 1, 07743 Jena — ²Otto-Schott-Institut für Glaschemie, Universität Jena, Frauenhoferstr. 6, 07743 Jena

media for diode pumped lasers. Several Er³⁺:Yb³⁺-doped fluoride phosphate glasses with different phosphate content were examined for their spectroscopic and lasing properties. Absorption and emission spectra of glasses were taken and respective cross sections calculated. Maximum output powers of 120 mW at slope efficiencies of up to 21 % were obtained in a hemispherical resonator configuration. Concentration ratio for best lasing behavior of erbium glasses was found at low Er³⁺- (5×10¹⁹ cm⁻³) and high Yb³⁺-content (8×10²⁰ cm⁻³). Energy transfer between Yb³⁺- and Er³⁺-ions was examined by spectrally resolved fluorescence decay measurements, with efficiencies between 78 % and 92 % depending on doping level. Wavelength tuning range was 100 nm with 0.3% output coupling loss. Thermal effects can severely limit performance of laser glasses due to their low thermal conductivity. Pump induced heating of samples was calculated by solving the thermal transport equation. The temperature sensitive ratio of the ²H_11/2 to the ⁴S_3/2 green upconversion fluorescence intensity can be used to experimentally verify calculated results. Analysis of the resulting damage by thermal stress and heating is presented.