Vortex beam generation from reduced graphene oxide(rGO)-polymer

We have obtained reduced graphene oxide (rGO) by reducing the graphene oxide (GO) polymer using a femtosecond (fs) pulse laser. A method for the fabrication and preparation of GO-polymer composite is first described. We then discuss the reduction of GO-polymer to rGO using direct laser writing technology. We have characterized a fabricated rGO binary phase grating and shown that the degree of the photoreduction of GO-polymer to rGO-polymer can be controlled by the laser power. Phase modulation has been found to be more than 2π/3. Finally, we have designed a computer-generated hologram to realize an rGO fork grating. Upon illumination of the grating, a vortex beam is generated through diffraction.