Absorption saturation and photodarkening in semiconductor-doped glasses

Abstract

Transmission measurements show a large decrease of the absorption saturation in semiconductor-doped glasses which have been exposed to intense absorbing light. A simple saturation model including nonradiative and Auger recombination and an unsaturable part of the absorption, interpreted as free-carrier absorption, explains the observed changes.

Laser power dependence of the photoluminescence from CdSxSe1-xnanoparticles in glass

“…Apart from the recombination at the band-gap, we have identified transitions involving deep traps associated with the surface states and the defect states. Luminescence from the deep traps shows an effect of photodarkening [5,[16][17][18][19] under strong laser illumination. Several inconsistencies in the literature concerning the relaxation dynamics of photoexcited carriers seem to be due to this photodarkening process, which is manifested in a decrease of luminescence after a strong illumination of the sample.…”

“…Several inconsistencies in the literature concerning the relaxation dynamics of photoexcited carriers seem to be due to this photodarkening process, which is manifested in a decrease of luminescence after a strong illumination of the sample. The authors have explained this effect in terms of a permanent trapping of the carriers [17][18][19] and in terms of an increase in non-radiative recombinations [20]. The optical properties of the material are permanently changed in such a process; however, they can be partially restored by a heat treatment.…”

Optical properties of quasi-zero-dimensional CdSXSe1-X crystallites grown in a glass matrix

“…46 '47 To analyze the influence of competing processes on the light absorption saturation, one can assume that linear recombination is the dominant mechanism in the CdSSe1 -x microcrystals. 46 '47 To analyze the influence of competing processes on the light absorption saturation, one can assume that linear recombination is the dominant mechanism in the CdSSe1 -x microcrystals.…”

Nonlinear Properties of Semiconductor-doped Glasses

“…The largest nonlinear effects are at wavelengths close to the absorption edge [4,5] . A complicating factor is the longterm darkening of the glass that may eventually occur when a sample is exposed to high-intensity radiation [2,10] . The damage can be annealed out by high-temperature treatment, but its presence means that the sample must be frequently changed .…”