Valentin K. Bogdanov

Fluorescence from highly-doped erbium fluorozirconate glasses pumped at 800 nm

Abstract A study of the fluorescence properties, under 800 nm excitation, of new ZBEAN glasses with Er 3+ concentrations up to 18 mol% is reported. This represents the highest reported doping concentration for this type of glass. The fluorescence intensity at 550 nm, 1.53 μm and 2.7 μm did not exhibit the expected strong quenching at these high concentrations and the corresponding decay times were consistent with this observation. Cooperative energy transfer between the relevant levels is discussed as a possible explanation of this behaviour.

High Er(III) content ZBN glasses for microchip laser applications

Abstract The preparation and properties of zirconium/barium/sodium fluoride glasses containing high Er(III) contents are discussed in detail. Glasses containing up to 33×10 20 Er(III) cm −3 (18 mol%) have 1530 nm fluorescence lifetimes in the region of 10 ms and show no evidence of concentration quenching in their emission at various wavelengths in the infra-red. The lack of substantial concentration quenching was an unexpected result and possible reasons for this are discussed.

High erbium content heavy metal fluoride glasses

Abstract Rare earth glasses with high doping concentrations are candidates for the production of eye-safe microchip lasers for use as transmitters and detector amplifiers in laser radar systems and as transmitters in ultrahigh data rate communication systems. Presently only low concentrations of rare earths have been incorporated into glass hosts but microchip lasers will require higher dopant concentrations in order to obtain sufficient absorption of the pump radiation. In this work, glass systems based on ZrF4 were found to be able to support dopant concentrations of ErF3 up to 18 mol%. The thermal, optical and absorption properties of these ZBEAN glasses are examined as a function of concentration.

Energy exchange processes in Er3+-doped fluorozirconate glasses

Abstract A comprehensive study has been conducted on the effects of erbium dopant concentration on the fluorescence properties of the three lowest energy levels which are involved in infrared emission in Er3+-doped fluorozirconate glass compositions. Pulsed pump radiation at wavelengths of 800 nm, 980 nm and 1.5 μm was used to measure fluorescence rise and decay waveforms for Er3+ concentrations between 0.2 and 18 mol%. A rate-equation model has been developed for the relevant levels and the fitting of this model to the experimental results has enabled the contribution of various ion–ion energy exchange processes to be identified and quantified. These processes determine, in part, the population dynamics, especially for the larger dopant concentrations used.

Energy transfer in praseodymium and neodymium co-doped fluorozirconate glass

Abstract Energy transfer parameters have been determined for a praseodymium (Pr 3+ ) and neodymium (Nd 3+ ) co-doped fluorozirconate glass. Fluorescence decay from the 3 P 0 state of Pr 3+ and 4 F 3/2 state of Nd 3+ was fitted to the solutions of a set of simple rate equations. The parameters allow the quantification of two-ion energy transfer processes involved in both intra- and inter-dopant interactions. A knowledge of these parameters is essential for understanding and modelling the optical processes concerned with the 3 P 0 state of Pr 3+ and the 4 F 3/2 state of Nd 3+ . A three-ion energy transfer process was also observed but an associated parameter could not be quantified.