Abstract: A process and photoactive media for holographic recording and micro/nanofabrication of optical and bio-optical structures via the simultaneous absorption of two-photons by the photoactive media to induce a simultaneous photochemical change in regions of constructive interference within a holographic pattern is disclosed. The photochemical process of polymerization resulting from the simultaneous absorption of two-photons may be used for the microfabrication of micro and nanoscaled features, holographic data storage, and the formation of switchable diffraction gratings.

Abstract: A new photopolymerizable material allows single-step, fast recording of volume holograms with properties that can be electrically controlled. Polymer-dispersed liquid crystals (PDLCs) in accordance with the invention preferably comprise a homogeneous mixture of a nematic liquid crystal and a multifunctional pentaacrylate monomer, in combination with photoinitiator, coinitiator and cross-linking agent. Optionally, a surfactant such as octanoic acid may also be added. The PDLC material is exposed to coherent light to produce an interference pattern inside the material. Photopolymerization of the new PDLC material produces a hologram of clearly separated liquid crystal domains and cured polymer domains. Volume transmission gratings made with the new PDLC material can be electrically switched between nearly 100% diffraction efficiency and nearly 0% diffraction efficiency. By increasing the frequency of the switching voltage, switching voltages in the range of 50 Vrms can be achieved.