Er3+ fluorescence in rare-earth aluminate glass -: art. no. 043521

Er3+ ion fluorescence was excited with a 980-nm pump laser in Er-doped rare-earth aluminate (REAl) glasses with Er-dopant concentrations from 0.5-30 mol % (oxides basis). The spectral and decay characteristics were measured at similar to 1550 nm from Er3+ I-4(13/2) and at similar to 2750 nm from Er3+ I-4(11/2). Red and green light emissions were also observed, from Er3+ F-4(9/2) and S-4(3/2)+H-2(11/2), respectively. The fluorescence decay rates are described by a model that yields an accurate fit of results at Er concentrations from 0.5 to 7 mol %. The radiative lifetime of Er3+ I-4(13/2) in Er:REAl glass is 6.12 +/- 0.26 ms. Hydroxyl ion quenching occurs at a rate given by 9.88x10(-20) a(OH)n(Er) Hz, where a(OH) is the glass absorption coefficient (in cm(-1)) at a wavelength of 2950 nm and n(Er) is the total Er ion concentration. The I-4(13/2) upconversion rate constant increases with the Er concentration to 1.35+0.05x10(-18) cm(3)/s at and above 7-mol % Er2O3. Er3+ I-4(11/2) fluorescence decays primarily by multiphonon quenching to I-4(13/2), at 7700 +/- 800 Hz, a rate that is slightly less than in tellurite glasses. The addition of 20-mol % silica to the glass has only a small influence on the fluorescence decay rates and greatly improves glass formation from the liquid to allow melting and casting of Er-doped REAl glass from platinum crucibles. The application of these Er-doped glasses in laser and optical device applications is briefly discussed. (c) 2005 American Institute of Physics.