Experimental observation of enhanced reverse saturable absorption in Bi ₂ Se ₃ nanoplates doped PMMA thin film

Abstract

By employing the ultrafast Z-scan technique, we characterize the nonlinear absorption property of PMMA/Bismuth Selenide (Bi2Se3) composite with varying concentrations. We report the fabrication of bismuth selenide (Bi2Se3) nanoplate (topological insulator (TI)) doped poly methyl methacrylate (PMMA) thin film with varying doping concentrations. The effect of Bi2Se3 on structural and linear properties of PMMA thin film has been investigated through UV-Vis spectroscopy, scanning electron microscope (SEM), and Energy dispersive X-ray spectroscopy (EDS) elemental mapping techniques. Furthermore, the nonlinear optical absorption property of PMMA and PMMA/Bi2Se3 composites have been performed employing a single beam open aperture z-scan technique under femtosecond laser excitation at 750 nm. The z-scan results exhibit an enhancement of reverse saturable absorption (RSA) property with an increased nonlinear absorption coefficient (β) of the PMMA/Bi2Se3 composites compared to pure PMMA measured with intensity at 320 GW/cm2. The RSA response gets enhanced with the increase in doping concentration also. Our experimental observations reveal that PMMA/Bi2Se3 composite can provide promising a platform to realize photonic devices such as optical limiters, optical switches, and efficient protectors from high power sources.