READ TIMES FOR BACTERIORHODOPSIN-FILM OPTICAL CACHE MEMORY

We report measurements of nonlinear-optical responses of bacteriorhodo psin (BR) films of long intermediate-state lifetimes. Nanosecond-durat ion pulses were used as the excite beam and cw monochromatic light was used as the probe beam in excite-probe experiments. The results revea l that, whereas the response time of the BR films is of the order of m illiseconds at the probe wavelength of 633 nm used in earlier experime nts, it is of the order of 100 mu s at probe wavelengths of 600 nm and below. Contrast ratios and insertion losses were also measured at dif ferent probe wavelengths and probe irradiance levels; the maximum cont rast ratio was found to be similar to 3:1. The implications of these r esults for the application of BR films as optical cache memory devices are discussed. (C) 1997 Optical Society of America.