Optical near-field excitation using liquid crystals on nanostruc- tured photoreactive molecular thin films

Optical near-field excitations were investigated on the basis of molecular alignment control of liquid crystals （LCs） on an optically rewritable nanostructure of photoreactive molecular thin films. Twisted nematic （TN） cells of LC molecules were con- structed utilizing ITO substrates with 260 nm gratings of an azobenzene molecular thin film, fabricated using standing evanes- cent waves. The polarization changes of light transmitted through the TN cells, which were due to the alignment changes of LC molecules locally rubbed by the azobenzene nanogratings, were observed. Furthermore, we demonstrated local plasmon excitation of Au nanowires deposited on the azobenzene nanogratings using oblique vacuum evaporation, a phenomenon that produced strong anti-optical absorption spectra. The modulation of the local plasmon resonance in metallic nanowires deco- rated with LC molecules was confirmed.