Investigation Of Photochromism And Photoinduced Anisotropy Of Diarylethene And Its Applications

The applications of new type of photochromic materials in optical storage andswitch arouse much interest of investigators. Because of the indispensable optical andphotoelectric properties, predominant thermal irreversibility and fatigue resistance,diarylethene is attention-getting in scientific research as a well-known photochromicmaterial. A serie of investigations, including the theoretical and experimental studieson the photochromic and photoinduced anisotropy of diarylethenes, are completed inthis thesis, which are summaried in the following:1. The photochromic characteristics of diarylethene film are studied. Firstly, theabsorption mechanism of the two-steady-state is analyzed. Using the two-steady-stateabsorption spectra, the change of the refractive index spectra are calculated by theK-K relation. Secondly, using the two-state models, the photochromic kineticfunctions of transmission are given, in the basis of which the the photochromic kineticcharacteristic are studied. Based on the theoretical and experimental results, theeffective photochemical conversion constants are simulated. Finally, the fatigueresistance of photochromic diarylethene/PMMA film is studied.The theoretical andexperimental results indicate that the kinetic process of photochromic diarylethene isexposure-dependent, thereby, the best parameter are obtain as used in the opticalstorage and information processing.2. The characteristic of photoinduced anisotropy of diarylethene are studied.Firstly, the process of photoisomerism is anylisised via the polarization UV-VISspectra, that is, the tropism of diarylethene molecules in the isomerized processes areanalyzed with the physical difference of the absorption spectra, by which themechanism of the photoinduced anisotropy is clarified. Secondly, the mathematicsfunctions of the photoinduced anisotropy of diarylethene are given, by which thekinetic curves of photoinduced dichroism and birefringence are calculated, as well asthe influence of the polarization state of excitation beam on the photoinducedanisotropy is investigated, and the experimental results are accord with the theoretical calculation. Finally, based on the properties of photoinduced anisotropy ofdiarylethene film, the optical image processing is realized, such as the contrastreversal, low-pass filtering and edge-enhancement. The optical modulation is realizedwith different photoinduced anisotropy produced by different polarizations ofexcitation beam.3. The properties of two-photon absorption in diarylethene film are studied.Firstly, the conception of two-photo absorption for the organic photochromic materialis described, and the theory is analyzed. Secondly, the properties of two-photonabsorption in diarylethene film are studied. The theoretical analysis of two-photoabsorption is carried through, and the experiment of photochromic properties and thekinetics of photoinduced anisotropy are performed also. Finally, the application oftwo-photon absorption of diarylethene in optical storage is preliminarily tested.4. The holographic optical storage of diarylethene films is studied. Firstly, thediffraction efficiency of holographic gratings in diarylethene film is theoreticallyanalyzed. Secondly, the kinetics of polarization holographic recording isexperimentally measured and the influences of recording and reconstruction beams onthe diffraction efficiency of holography grating are analyzed, and the diffractionefficiencies of different polarization gratings are compared. Thereout, the bestexperimental conditions and parameters are obtained for diarylethene in thepracticality optical storage. Finaly, different kinds of holographic multiplexingschemes, such as polarization multiplexing, angular multiplexing, peristrophicmultiplexing and polarization plus angular multiplexing are realized in diarylethenefilm.