Optical Properties And Application Of Bacteriorhodopsin

Bacteriorhodopsin (BR), a biomolecular material, has the unique photochromic properties. This photosensitive protein holds the all-around advantage compared with other organic photochromic materials. It is one of the important materials in the field of optical signal processing and optical storage. Focusing on the photochromic properties and applications of bacteriorhodopsin film, the author mainly completed the following works:1. The photochromic properties of BR-D96N film and its application in optical image storage were studied. The absorption spectra of the two states were measured. The spectrum of refractive index changing appearied during the photochromic reaction in this film is calculated according to the Kramers-Kronig transformation. The absorption spectra of the sample at different time in the thermal delay process after light excitation are measured with spectrophotometer. By fitting and analyzing the absorption spectra, the absorption spectra of the B state, M state and D state were extracted from the experimental data. By fitting the spectra at various time with the least square method, the variations of population percentages of the M state, B state and D state molecules with the time in the thermal delay process are obtained and the lifetimes of M state and B state are estimated. Then, from the absorption dynamics at 411nm and 568nm, the lifetimes of M state and B state are obtained by two exponential data fitting. And the optical image storage was realized in BR-D96N film by using its photochromic properties.2. The holographic storage properties of BR-D96N films were studied, which were respectively based on the photochromic and photoinduced anisotropy properties. The diffraction polarization state and diffraction efficiency of different kinds of polarization holograms were theoretically analyzed and deduced. And the ordinary holographic efficiency of BR-D96N films was theoretically calculated by using MATLAB softwere.3. The experimental study of holographic image storage: different kinds of holograms were recorded in a BR- D96N film by using different kind of holographic storage technologies, including transmission-tape holographic recording and reflection-tape holographic recording technology, reference beam reconstruction and phase conjugated beam reconstruction technology, and different kind of polarization holographic recording technologies ( i.e. parallel linear polarization holographic recording, orthogonal linear polarization holographic recording, parallel circular polarization holographic recording and orthogonal circular polarization holographic recording etc.). The diffraction efficiencies and diffractive images' signal-to-noise-ratios of different kinds of holograms are compared. And the phase conjugated beam reconstruction can effectively correct the phase aberration caused by the mis-adjustment of optical setup were also studied.4. The polarization multiplexing holographic recording was realized, i.e. two object images with orthogonal polarizations were recorded at the same position on the sample as two different holograms respectively, which can be selectively retrieved. And it is demonstrated that image subtraction and summation processing can be realized by using polarization multiplexing holographic recording method, and keystone (basic elements) were given.