Optical Computation with Negative Light Intensity with a Plastic Bacteriorhodopsin Film

• Published in: Science (American Association for the Advancement of Science) Vol. 275; no. 5305; pp. 1462 - 1464
• Main Authors: Lewis, Aaron, Albeck, Yehuda, Lange, Zvi, Benchowski, Julia, Weizman, Gavriel
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 07.03.1997; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Astronomical objects; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Laplacians; Laser beams; Lasers; Light; Luminous intensity; Material films; Materials; Optical computers, logic elements, interconnects, switches; neural networks; Optical data processing; Optical elements, devices, and systems; Optical films; Optical lenses; Optical materials; Optics; Photons; Physics; Proteins; Rhodopsin; Subtraction; Wavelengths; Bacteriorhodopsin; Biological compound; Optical computing; Theoretical study; Optical materials; Bistable; Experimental study; Photoprotein
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.275.5305.1462

The inability to use light intensity to represent negative values limits the potential of optical computing. The protein bacteriorhodopsin, an optically switchable bistable material, was used to represent an image as a local concentration of one of its two states. Light of one wavelength increased this concentration and represented positive intensity, whereas light of a different wavelength decreased the concentration and represented negative intensity. Optical subtraction was demonstrated by performing the mathematical operation of a difference of Gaussians. The electro-optical characteristics of bacteriorhodopsin films portend a variety of practical applications for this system