Papers by Author: Hiroshi Ono

Abstract: Nonlinear light propagation in a dye-doped liquid crystal (LC) was investigated experimentally. A laser beam with wavelength far from the absorption peak of the material was coupled into an LC cell with homogeneous alignment, and the propagation in the cell was observed. When the polarization azimuth of the incident light was orthogonal to the orientation direction of the LC, soliton-like propagation was obtained for milliwatts of light power in spite of the low absorption. We clarified that the observed nonlinearity is due principally to the photothermal effect enhanced by the dye.

Abstract: Light propagation in an optical waveguide fabricated by employing a dye-doped liquid crystal (DDLC) was observed. The propagation of a light signal in the waveguide was varied by irradiation with a control light whose wavelength was in the absorption band of the DDLC. By considering the photothermal effect of the DDLC, which enables the change of the refractive index due to temperature variation based on the absorption of light, we qualitatively explained the observed light propagation and demonstrated manipulation of the propagation.

Abstract: One-dimensional multiplexed anisotropic gratings were fabricated in photoreactive polymer liquid crystals (PPLCs), and the diffraction properties were characterized. Based on the holographic technique, the overwriting process is combined with the highly-stable and –controllable molecular alignment of the PPLCs. As a result, 1st- and 2nd-order diffraction intensities variable gratings dependent on the polarization direction of probe beam were obtained without significant changing their total diffraction intensity. The multiplexed gratings can be used as polarization-selective diffractive optical elements.