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Optical Engineering

All-optical nonlinear holographic correlation using bacteriorhodopsin films
Author(s): Ralph Thoma; Michael Dratz; Norbert A. Hampp
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Paper Abstract

Films made of the halobacterial photochrome bacteriorhodopsin (BR) can be used in a number of holographic real-time applications. Their application as active material in a dual-axis joint-Fourier-transform (DAJFT) real-time correlator was shown recently. The BR films have a strong nonlinear intensity dependence on the light-induced absorption and refractive-index changes. Therefore the holographic diffraction efficiency also shows a nonlinear dependence on the writing intensity. We investigate the effect of this nonlinearity on the result of the correlation process in a bacteriorhodopsin-based DAJFT correlator. Numerical models supporting the experimental observations are presented. It was found that the BR film combines the holographic function for most objects with that of a spatial bandpass filter, whose center frequency is tuned by the writing intensity. This results in smaller peak widths and a suppression of the sidelobes. BR films allow the application of this nonlinear behavior in real time to the all-optical correlation process.

Paper Details

Date Published: 1 May 1995
PDF: 7 pages
Opt. Eng. 34(5) doi: 10.1117/12.201654
Published in: Optical Engineering Volume 34, Issue 5
Show Author Affiliations
Ralph Thoma, AGFA-Gevaert AG. (Germany)
Michael Dratz, Univ. of Munich (Germany)
Norbert A. Hampp, Univ. Muenchen (Germany)


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