Polarization-controlled images based on double-exposure polarization holography in an azobenzene liquid-crystalline polymer

Abstract

Polarization-controlled optical image operations were demonstrated based on the double-exposure polarization holographic method. Two images were stored in the same volume of an azobenzene liquid-crystalline polymer by recording superimposed holograms, a pair of polarization gratings with one spatial frequency, using two orthogonal circularly polarized 532 nm beams and were reconstructed with a 650 nm laser. The recorded polarization holographic gratings were investigated to show distinctive polarization selectivity, high diffraction efficiency, and good stability. The brightness and the polarization of the diffracted images were found to be dependent on the polarization of the readout beam, and two images could be reconstructed individually or simultaneously.

Molecular design of azo-carbazole monolithic dyes for updatable full-color holograms

“…In addition, other photonic applications such as holographic memory, optical switches and waveguides have been proposed. [1][2][3][4][5] Examples of updatable holography include azobenzene molecules in polymer matrices, [6][7][8] liquid crystals, 9,10 polymeric liquid crystals [11][12][13][14][15] and photorefractive polymers. [16][17][18][19] In particular, azobenzene molecules are the most promising candidates for use in updatable holography because azobenzenes are well-known photosensitive chromophores that undergo trans-cis photoisomerization upon irradiation with light of an appropriate wavelength in a solution or in an appropriate host matrix.…”

Azo-carbazole copolymer-based composite films with high optical transparency for updatable holograms

“…[1][2][3][4][5][6] In recent years, numerous studies have been conducted on materials that can be adapted to produce dynamic holograms, which are rewritable holograms that improve upon static holograms. Typical materials for updatable holograms include azobenzene molecules in a polymer matrix, [7][8][9] liquid crystals, 10,11 polymer liquid crystals, [12][13][14][15][16] and photorefractive polymers. [17][18][19][20] In particular, azobenzene molecules are the most promising candidates for updatable holography because they are well known as photosensitive chromophores that undergo trans-cis photoisomerization upon irradiation with light of an appropriate wavelength in solution or a host matrix.…”