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 ( Bi _2 Se _3 ) composite with varying concentrations. We report the fabrication of bismuth selenide ( Bi _2 Se _3 ) nanoplate (topological insulator (TI)) doped poly methyl methacrylate (PMMA) thin film with varying doping concentrations. The effect of Bi _2 Se _3 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/ Bi _2 Se _3 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/ Bi _2 Se _3 composites compared to pure PMMA measured with intensity at 320 GW cm ^−2 . The RSA response gets enhanced with the increase in doping concentration also. Our experimental observations reveal that PMMA/ Bi _2 Se _3 composite can provide a promising platform to realize photonic devices such as optical limiters, optical switches, and efficient protectors from high power sources.

Keywords

• nonlinear optics
• integrated Photonics
• Z-scan technique