Continuous wave laser induced nonlinear optical response of nitrogen doped graphene oxide

This study reports the investigations on linear and nonlinear optical (NLO) properties of graphene oxide (GO) and nitrogen doped graphene oxide (N-GO) obtained by a simple pyrolysis method. The third order nonlinear optical properties of GO and N-GO were studied using continuous wave (CW) laser operating at 532 nm wavelength by employing the Z-scan technique. The nature of the curves suggests that the GO and N-GO exhibits reverse saturable absorption (RSA) and negative nonlinear refractive (NLR) index. Further, nitrogen incorporation has significantly enhanced the nonlinear absorption coefficient (beta) values. Variation in the localized sp(2) cluster size within the sp(3) domains are accounted for the optical energy gap which is determined by the Tauc plot. The fluorescence intensity and their relative quantum yields are largely influenced by nitrogen in sp(2) sites studied using Light emitting diode (LED) as a source at an excitation wavelength 452 nm. This cost effective N-GO material with giant linear and nonlinear optical properties may become significant in bio-imaging, biosensor, optical switching devices and NLO based applications.