Advances in protein-based three-dimensional optical memories

An oriented bacteriorhodopsin cube is optimized as a potential three-dimensional optical memory medium. Write/read capability is demonstrated by using the photovoltaic signal induced by two-photon absorption. Our results demonstrate that a two-photon induced photovoltage can he detected in a three-dimensional Bacteriorhodopsin (BR) cube as large as 1.6 × 1.6 × 1.6 cm3. The read/write speed, signal to noise ratio, and the laser damage threshold for the protein-based three-dimensional optical memory is examined.