2008 年 124 巻 10_11 号 p. 633-639
We report our recent results on the photoinduced transient optical absorption measurements of amorphous (a-) As2Se3 and a-As2S3, after the illumination of nanosecond pulsed laser. From the measurements, we have observed a photodarkening in the nanosecond and microsecond domains for the first time. Since the fast photodarkening was also observed in the liquid state, the structural origin of the photodarkening should be different from the conventional metastable photodarkening, which is observed only below the glass transition temperature. We have also examined accumulated photoinduced changes for the stronger repeated pulsed laser illumination. From the measurements, we have found for As2S3 that there exists an accumulated photoinduced absorption in the supercooled liquid state. On the basis of the detailed results of the transient optical absorption measurements, structural origin of the photodarkening is discussed.