Photonic crystals based on holographic polymer-dispersed liquid crystal films and applications

The superprism and lasing devices were demonstrated using holographic polymer-dispersed liquid crystal (HPDLC) films. The HPDLC film for superprism application was designed and fabricated using three coplanar beams. The fabricated HPDLC film contained two-dimensional (2D) ordered nano-sized LC domains (~150nm in diameter) embedded in a polymer matrix; its periodicity was estimated using a scanning electron microscope to be ~350nm. The dispersion of white light from this HPDLC superprism was ~50°, and the deflection of light output from it was consistent with the theoretical value obtained by the pland wave expansion method. HPDLC for laser application was fabricated using two counter-propagation laser beams similar to those used in standard holography. The structure has a periodicity in the range of optical wavelength, and reflects light selectively as governed by Bragg reflection. Doped with a laser dye whose emission spectrum overlaps the reflection spectrum of the grating, the HPDLC reflection grating can be lased at the band edges of the reflection band gap. The details of the experiments, results will be reported.