Dynamic polarization grating based on a dye-doped liquid crystal controllable by a single beam in a homeotropic-planar geometry.

We present a dynamic polarization grating based on a dye-doped liquid crystal cell that is controllable by a single pump beam in a binary homeotropic-planar configuration produced through selective rubbing. Upon single pump beam irradiation, the azo dyes in the liquid-crystal (LC) layer diffuse and adsorb onto the planar LC-anchoring surface due to trans-cis photo-isomerization. It is found that the dynamic polarization grating effect results mainly from the photo-induced easy axis reorientation by the amount of dye molecules adsorbed on the planar LC-alignment surface in a single-beam control scheme. The initial LC-anchoring conditions and the dynamic behavior of the dye adsorption strongly influence the repetitive writing-erasing processes by the single pump beam.

Spatial patterning of fibroblast cells with fabricating holographic patterning on the photoresponsive polymer.

Micro topographic feature was obtained by laser holographic fabrication on the photoresponsive polymer. Surface feature was localized using photomask for developing two dimensional cellular pattering. Fibroblast cells were cultured and proliferated only on the patterned substrate. Obtained cellular pattering suggests that the laser fabricating with photoresponsive polymer would be applied to regenerating new tissue and developing biomedical device of living cells.

Photo-triggering of the membrane gates in photo-responsive polymer for drug release.

The use of light stimulus for triggering drug is a promising method for accurate drug delivery. A new approach using azopolymer membrane and laser holography was investigated for developing light-triggering drug delivery system. Polymeric drug delivery system was prepared by covering azopolymer membrane on a drug agent. Holographic laser interference generated surface relief grating pattern on the azopolymer surface. The widths and depths of gates on the polymer membrane were easily modified by adjusting incident angle and irradiation time. Ar laser made the polymeric membrane permeable to the drug agent and release it in a solution. This result indicated that the azopolymer and laser holography would provide a strong foundation for the light-triggering drug delivery system.