Metallic 3D Random Nanocomposite Islands For Near-Field Spatial Light Switching

Random nanocomposite islands have drawn significant interest for diverse applications due to extreme simplicity of fabricating nanoscale structures. In this paper, the near-field characteristics of random nanoislands produced by spatial light switching are investigated, with light incidence switching among 14 incident channel modes. The results show that localized light fields are displaced from nanoislands almost linearly with the incident angle of channels. Also, light fields rotate in a manner aligned to the direction of light incidence. Ten-channel spatial switching is found to provide coverage of near-fields on the surface close to 90%. The numerical data are experimentally validated using fluorescent imaging and near-field scanning optical microscopy. The results suggest the possibility of using random nanoislands for high performance imaging such as superresolution microscopy and molecular detection techniques.