High-performance all-optical switching based on nonlinear response in semiconductor Bi2S3-xSex/PMMA nanocomposite films

Abstract

ABSTRACTWe present an optical pump-probe technique to optimise the all-optical photonic switching based on Bi2S3-xSex/PMMA nanocomposite films. Bi2S3-xSex/PMMA nanocomposite films were prepared using a microwave-assisted synthesis with different compositions of x. Crystal structure, surface morphology, and optical properties were performed to characterise the prepared nanocomposite films. The crystallinity and optical band gap of the prepared Bi2S3-xSex/PMMA were affected by x. The prepared samples showed a blue shift in the absorption edge. The optical nonlinearity of the films exhibited switchover from self-defocusing to focusing effect, and saturable absorption to reverse saturable absorption, investigated using the Z-scan technique. The all-optical switching performance of the Bi2S3-xSex/PMMA nanocomposite films under different compositions x was investigated. The results showed that the Bi2S3-xSex/PMMA at x = 0.4 and 1.0 can demonstrate an all-optical switching at threshold pump power of 13 mW and lead to the realisation with maximum modulation depth of 76% and 80% with minimum switching contrast of 6.2 dB and 7 dB at switching time of 14 ms and 13 ms, respectively.