Near-infrared nonlinear optical response of some carbon-based nanomaterials

ABSTRACT The nonlinear optical response of some carbon-based nanomaterials, namely some nanodiamonds and carbon nanoparticles (C-dots) are investigated using infrared nanosecond laser pulses. Both nanocarbons had similar sizes (< 10 nm) and exhibited measurable nonlinear absorption and refraction. Their optical limiting behaviour has been also investigated. Nanodiamonds were found to exhibit remarkable optical limiting response in the infrared, being therefore promising candidates for potential opto-electronic and photonic applications. Keywords : nanodiamonds, carbon-dots, nonlinear optical properties, optical limiting, Z-scan. 1. INTRODUCTION Since their discovery, the allotropic forms of carbon have become a class of materials which has attracted greatly the scientific interest and hence, they are studied intensively. The allotropes of carbon exhibit several unexpected and interesting properties, with the emphasis in the previous studies given in their mechanical, electrical and optical ones. It is only recently, after the discovery of fullerenes, that the nonlinear optical (NLO) response of these materials has attracted more interest. So, although fullerenes, carbon nanotubes and graphene (lastly) have been systematically investigated for their NLO properties [1]-[2], similar studies concerning nanodiamonds (NDs) and carbon dots (CDs) NLO response remain scarce until very recently. A very important property of these carbon-based materials is their optical limiting (OL) behaviour when excited with laser pulses, this behaviour being associated either to multi-photon and excited-state absorption processes or to different nonlinear optical scattering mechanisms. The motivation of the present work was to investigate the NLO response and the OL action of these carbon-based nanodiamonds and dots, to compare them with other organic materials and provide some understanding to the physical mechanisms which determine their NLO response.