# Coexistence of fast photodarkening and slow photobleaching in Ge19As21Se60 thin films

Source: [Coexistence of fast photodarkening and slow photobleaching in Ge19As21Se60 thin films](<https://www.sota2.com/research/paper/68fa2d2c1e209131ce856cba>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-27T03:23:05.925Z

Authors: Pritam Khan, A. R. Barik, E. M. Vinod, K. S. Sangunni, H. Jain, K. V. Adarsh

Published: 2014-03-25T14:28:18.000Z

## Abstract

We experimentally demonstrate the coexistence of two opposite photo-effects, viz. fast photodarkening (PD) and slow photobleaching (PB) in Ge19As21Se60 thin films, when illuminated with a laser of wavelength 671nm, PD appears to begin instantaneously upon light illumination and saturates in tens of seconds. By comparison, PB is a slower process that starts only after PD has saturated. Although we could observe the coexistence of PD/PB even at moderate, one order of magnitude lower intensity of 0.2 W/cm2, the kinetics of transformation is significantly slowed down. However, both PD and PB follow stretched exponetial dependence on time. Modeling of overall change as a linear sum of two contributions suggests that the changes in As and Ge parts of glass network respond to light indepndent of each other.

## Recorded benchmark results

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1403.6359>)

[PDF](<https://arxiv.org/pdf/1403.6359.pdf>)