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A three-laser-beam technique is developed to study the transient diffraction efficiency of M-state dynamic phase holograms in a D96N mutant bacteriorohodopsin film (BR). A CW beam from 532 nm doubled Nd:YAD laser is used to pump BR molecules from B-state to photoexcited M-state. Then the M- state absorption laser 413-nm wavelength from a Krypton Ion laser is used to write holographic gratings in the excited M- state. The writing process also depletes M-molar concentrations. This process offers the advantages of better modulation and faster response. The reading is done with a 680 nm laser, which is far away from the absorption bands to ensure a negligible erasing effect on the gratings written in the film, resulting a pure phase hologram with high efficiency. A maximized transient peak diffraction efficiency approaches a saturated value when the ratio of write to pump intensity is approximately unity.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
