Role of thermal and photoannealing on nonlinear optical response of Ge30Se55Bi15 thin films

Abstract

In this article, we employed the nanosecond Z-scan technique to demonstrate the nonlinear optical response in Ge30Se55Bi15 thin films after\nthermal and photoannealing. The intensity dependent open aperture Z-scan traces reveal that all the samples, i.e., as-prepared, thermal, and\nphotoannealed thin films, exhibit reverse saturable absorption. The experimental results indicate that both thermal and photoannealing can\nbe efficiently used to enhance the nonlinear absorption coefficient (β) compared to the as-prepared sample. We further demonstrate that\nthe β value of thermally annealed and as-prepared samples increases significantly at higher intensities. On the contrary, the β value of the\nphotoannealed sample does not exhibit appreciable changes against the intensity variation.

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