“…Therefore, many methods have already been used to modify graphene, including different strategies for tailoring its shape [5][6][7][8], defect control [9][10][11], chemical modification [12][13][14][15], besides many others. Recently, an all-optical method, namely, two-photon oxidation of graphene was demonstrated, which proved to have some advantages as compared to other oxidation methods, including direct writing of device features with sub-micrometer resolution, high speed and controlled level of oxidation [16][17][18][19]. Previous atomic force microscopy (AFM), Raman and X-ray photoelectron spectroscopy (XPS) studies showed a two-photon oxidation process starting with point-like functionalized sites evolving into oxidized islands and then forming a uniform graphene oxide (GO) material mainly composed of hydroxyl (OH) and epoxide (C−O−C) functional groups with a few per cent of carboxylic (COOH) groups [17,18].…”