Broadband optical power limiting with the decoration of TiO2 nanoparticles on graphene oxide

Graphene, in its pristine form and analogs, is revolutionizing the architecture and designing of materials for highperformance optoelectronic devices. The functionalization of graphene is very attractive and emerging field of interest for nonlinear optical devices. In this work, we have synthesized Graphene oxide (GO) decorated with TiO2 semiconducting nanoparticles for nonlinear photonic devices. The nonlinear optical (NLO) measurements of GO-TiO2 composite were studied with a popular Z-scan technique for optical power limiting applications. Functionalized graphene oxide with TiO2 nanoparticles exhibits a strong enhancement in optical-response with nanosecond laser pulses. The composite show fingerprints of reverse saturable absorption (RSA) dominated by two-photon absorption (TPA) along with enhanced nonlinear absorption due to transfer of electrons/energy between TiO2 nanoparticles and graphene oxide. The systematic spectroscopic studies with TEM, XRD, FT-IR, micro-Raman, steady-state and time-resolved photoluminescence reveals that successful conjugation of GO and TiO2 nanoparticles and probes the structural and optical properties. The nonlinear optical measurements demonstrate that GO-TiO2 composite exhibits promising optical power limiting features than individual counterparts implicating the potential contingent towards broadband optical limiting applications.