Bacterial Rhodopsin Protein Polymer Composite Film Optical Properties, As Well As Applied Research, In Terms Of Photonic Devices

Bacteriorhodopsin(bR) is an active photochromic protein found in the purple membrane of the halophilic organism Halobacterium salinarium,bR has attracted much attention all over the world in recent years because of its unique properties in optics.And it has great prospects in applications such as optical devices and information memory.In this thesis,we discussed the optical properties of bR-Polymer Composite film(bR/PC film) and investigated the applications of bR in optical image display and optical switch.The main breakthroughs of our work in this thesis include: First,the photoinduced birefringence system was set up with the red,blue and green polarized laser beams as pumping-probing beams.We measured the birefringence property of the homemade bR/PC film and the high nonlinear coefficient was obtained.The value of^△n(change of refraction index) could reach 5.57^*10^-4 at 93mW/cm² pumping beam intensity when 476nm laser was chosen as pumping-probing beam wavelength.Within the low pump intensity range (I_pump＜90mW/cm²),the contrast ration CR of the maximum transmitted intensity to the minimum one could reach 350,which is a high value.At the first time,the multi pumping beams were utilized to modulate the molecules distribution in the sample film.Thus the transmitted signal of probing beam modulated could be increased, decreased or keeping stable.Second,the broadband all-optical image display was realized by photoinduced distribution change of refraction index.By mixing red,blue and green laser beams as one pumping-probing beam,the new color mixed could be displayed at certain gray scale.More complicated image with multi colors could be displayed by adjusting the wavelength and intensity of each probing beam and pumping beam.Based on the complex modulation by multi pumping beams,the image information processing can be realized,including positive,negative image display,image erasure and image alteration.Third,the controlling beam possessed the selectivity in switching the transporting beam of certain wavelength.Based on it,we could selectively switch the beam with specific color and shape by choosing the light parameters of the controlling beam.We also adopted more laser beams as one controlling beam to realize switching multiple transporting beams.Fourth,the four-wave mixing experiment was investigated on bR/PC film and the holographic image was displayed based on the experiment.