Stepanchikov D. Polarization properties of bacteriorhodopsin phototransformations for nonlinear spatial light modulation

In this thesis, the photoinduced anisotropy in bacteriorhodopsin (BR) films has been studied using simultaneous action of two exciting beams of various polarizations. The exciting beams has different wavelengths. One of the exciting beams activates solely the initial photocycle form bR570 and the other activates predominantly the longest-lived shortwavelength-absorbing photocycle intermediate M412. Photoinduced anisotropy is studied in the polymer films with genetic mutants D96N and D96E BR, reconstructed proteins 4-keto and 4-keto-D96N BR and in the films with chemical additions in a polymer matrix. Calculations of a diffraction efficiency of the amplitude-phase dynamic polarization holographic grating in the BR films are performed taking into account the molecular dichroism value of bR570 form and arbitrary relationship between intensities of the orthogonally linearly polarized recording beams. Polarization properties of the light adaptation process are revealed and explored by the dynamic polarization holography method. The multiplex simultaneous recording of two intensity gratings by using recording beam pairs with different light polarization is realized. For the media with reversible anisotropic photoselection, it is shown both experimentally and theoretically that diffraction efficiency is more than two times as large for two overlapping intensity holographic gratings recorded by mutually orthogonally polarized beam pairs as for ones recorded with parallel polarized beam pairs. It is shown that the use of the B-M-type anisotropy allow for the real-time selective blocking of image features having particular intensity.