Effects of anisotropic diffraction on micro-periodic structure composed of polymer and liquid crystal phases

抄録

A micro-periodic structure composed of polymer and liquid crystal (LC) phases is called holographic polymer dispersed liquid crystal (HPDLC) grating. The HPDLC grating has been applied for grating formation to obtain both high optical efficiency and electric switching function. Moreover, HPDLC grating shows polarization dependence in diffraction efficiencies against the incident polarization state of laser light. The anisotropic diffraction is modulated by the distribution of submicrometer-scale LC droplet in a polymer matrix using interferometric laser exposure. The refractive-index modulations in grating medium corresponding to the three dimensional directions are obtained by applying theoretical calculation based on the anisotropy for the experimental results of angular dependence of diffraction efficiencies in various grating structures. The anisotropy in grating medium is analyzed by connecting the experimental results of angular dependence of diffraction efficiencies with SEM observations in different grating spacing.