Optical limiting and nonlinear optical properties of gold-decorated graphene nanocomposites

• Au-decorated graphene nanocomposites with superior optical limiting performance with lower limiting threshold <1 J/cm2 than Au nanoparticles or graphene nanostructures.
• The electronic structure and optical properties of graphene remain unperturbed in metal–graphene composites when the interaction of graphene p-orbitals with metal d-orbitals is mitigated.
• Surfactant free, one pot synthesis of gold-decorated graphene by laser ablation in liquid.
• Graphene increases the viability of Au nanoparticles as an optical limiter by providing channels for faster heat dissipation.
• Both nonlinear absorption and nonlinear scattering contribute to optical limiting response.

Metal nanoparticle-decorated low dimensional materials can synergistically combine the nonlinear optical properties of metallic/inorganic nanostructures for enhancing the optical limiting performance. While many materials exhibit excellent optical limiting performance at a relatively higher fluence (>9 J/cm2), there is a still a dearth of optical limiting materials for protecting low damage threshold (<1 J/cm2) photonic devices. Although metal nanoparticle-decorated graphene hybrids are expected to resolve this issue, the rehybridization of metal d-orbitals and graphene p-orbitals often lead to undesirable changes in graphene’s electronic structure which adversely affect the nonlinear optical performance. Here, we demonstrate that d-orbitals of Au nanoparticles exhibit little or no rehybridization with graphene and result in an enhanced optical limiting behavior at a low fluence of ∼0.4 J/cm2, which is lower than most metal decorated graphene, carbon nanotube nanocomposites and metal nanoparticles. This optical limiting performance at a lower fluence is attributed to the excellent photo-absorption of Au nanoparticles combined with rapid thermalization of excited carriers by graphene.