Photoinduced motions in azo-containing polymers.

Photoalignment of Liquid-Crystal Systems.

Three-Dimensional Optical Data Storage Using Photochromic Materials.

Linear and Nonlinear Optical Properties of Photochromic Molecules and Materials.

All optical fabrication of Surface Relief Grating (SRG) on azobenzene functionalized polymer films is reviewed in this article. The uniqueness of the single step erasable photofabrication of large amplitude surface relief structures on azo polymer films is mainly due to the photoisomerization and photoanisotropic behavior of the azobenzene group. The design and synthesis of several classes of suitable azobenzene functionalized polymers for the SRG formation is presented. Experimental studies are carried out in a systematic manner to understand the chemical and physical intricacies involved in the SRG formation process. Structural requirements and their limitations for the efficient fabrication of SRGs on azo functionalized polymer films are also discussed. Understanding the fundamental mechanism of SRG formation on the azo functionalized polymer films enables us to make use of these structures in a variety of applications.

Surface relief structures on azo polymer films

A liquid crystal with an azobenzene moiety as a photoactive mesogenic unit is investigated in photoinduced birefringence. Measurements reveal that it possesses large magnitude of photoinduced birefringence (Δn∼10−2) and the characteristic of long-term optical storage. The resulting polarization information can be erased either by heating the sample to a temperature much higher than the glass transition temperature, or by optical method with a circularly polarized light. The mechanism of long-term optical storage is discussed in this letter.

Photoinduced birefringence and reversible optical storage in liquid-crystalline azobenzene side-chain polymers

Photoinduced anisotropy and polarization holography in azobenzene side-chain polymer

Biphoton holograms are recorded by a He–Ne laser in Methyl Orange and Ethyl Orange dyes on exposure to 514.5-nm argon-ion laser, and the dynamic of holographic recording is reported. The recording utilizes an unusual photochemistry that is due to either to a triplet–triplet transition from a long-lived triplet lower state of the cis configuration or a transition back to the trans state.

Biphoton holographic storage in Methyl Orange and Ethyl Orange dyes

Polar enhancement of the nonlinear-optical properties of fe2o3 microcrystallites

Push–pull azobenzene compounds were synthesized by the diazocoupling reaction, and low-power phase conjugation of azobenzene-compound-doped poly(methyl methacrylate) films was studied with a He–Ne laser at 632.8 nm. It is shown that this kind of polymer has appreciable third-order optical nonlinearity, with a χ(3) of approximately 10−4 esu in the tail of absorption.

Haosheng Fei

Papers

Photoinduced birefringence and reversible optical storage in liquid-crystalline azobenzene side-chain polymers

Photoinduced anisotropy and polarization holography in azobenzene side-chain polymer

Biphoton holographic storage in Methyl Orange and Ethyl Orange dyes

Polar enhancement of the nonlinear-optical properties of fe2o3 microcrystallites

Low-power phase conjugation in push–pull azobenzene compounds