Er3+ and Yb3+ doped active media for 'eye safe' laser systems

There is considerable interest in compact pulsed high peak power laser sour ces emitting at wavelengths near 1.55 mu m Rangefinders and other applicati ons with, free space propagation could be a benefit of such devices. The wa velength of around 1.55 mu m is in the eyesafe regime where significantly h igher purse energies can be used without damaging human eyes. Erbium- and y tterbium-doped YAG single crystals were obtained by the Czochralski method. The basis conditions of growth and the results of optical homogeneity meas urements of the obtained crystals are presented. This report describes also the effect of variations of erbium, ytterbium, chromium ions and glass bas e compositions on laser efficiency and the improved properties of a new gla ss base. The spectral properties and laser characteristics were investigate d Absorption spectra of Er3+- and Yb3+- doped active media were measured in the spectral range 190 to 5000 nm at room temperature. Excitation and lumi nescence spectra were also recorded at room temperature with a Jobin-Yvon s pectrofluorometer using a diode laser (Polaroid 4300, 980 nm, 1 W) as an ex citation source. The measurements of the lifetime of the Er3+ ions in the u pper laser level (I-4(13/2)) of the samples were made by the direct method with pulse excitation. (C) 2000 Published by Elsevier Science S.A. All righ ts reserved.