[Holographic recording properties of BR-D96N film]

BR-D96N was a genetically mutated product of bacteriorhodopsin (BR) with obvious improved photochromic effect. Compared with the wild type BR, BR-D96N had a lifetime of M state prolonged to 5 min, showing obvious saturation absorption and lower light intensity in saturation absorption (0.4 mW/cm(2)). In case of holographic recording, dynamic grating was recorded in the BR-D96N film, its characteristic parameter was not light exposure energy but light intensity. The writing time of the holographic grating depended on the recording light intensity. The higher the recording light intensity, the faster the grating builds up. Under a weak reconstruction light, the recording light intensity resulting in maximal diffraction efficiency was consistent with the saturation absorption intensity. The reconstruction light could partly erase the grating. With lower intensity of reconstruction light, higher diffraction efficiency (1.8%) could be reached, but the diffraction intensity was not high. To get highest diffraction intensity, a properly high intensity of reconstruction light was needed (80 microW/cm(2)). The result of these experiments showed that holographic images could be recorded on the BR-D96N film.