Observation of photobleaching and intensity dependent kinetics in Ge_(22)As_(22)Se_(56) thin films under sub-bandgap light illumination

摘要

We experimentally demonstrate photobleaching (PB) in Ge_(22)As_(22)Se_(56) thin films, when illuminated with a diode pumped solid state laser (DPSSL) of wavelength 671 nm, which is far below the optical bandgap of the sample. Interestingly, we found that PB is a slow process and occurs even at moderate pump beam intensity of 0.2 W/cm~2, however the kinetics remain rather different.