All-photonic switching based on selective input pump polarization states in Fe-doped PbS/PVA freestanding nanocomposite films

Abstract

A new optical pump–probe technique for all-optical switching is proposed based on three-selective input pump polarization states to pump material simultaneously. The new technique makes it possible to obtain efficient all-optical switching of nonlinear optical materials with very low signal background and increased stability of switching signals. Undoped and Fe-doped PbS/PVA freestanding nanocomposite films are prepared by a simple chemical method at different doping concentrations. The x-ray diffraction patterns and optical absorption spectra of the prepared films are examined. The crystallinity and optical band gap of the prepared Fe-PbS/PVA are found to be affected by Fe doping concentration. The all-optical switching effect of Fe-PbS/PVA freestanding nanocomposite films with various Fe concentrations was investigated. The proposed technique that demonstrates all-optical switching with three-input polarization states can lead to the realization of all-photonic switching at a threshold optical pump power of 19 mW with maximum modulation depth (ON/OFF) of 86% and switching contrast (ON/OFF) of 8.6 dB for a minimum switching time of 43 ms.