Secure optical memory system with polarization encryption

A novel secure holographic memory system with polarization encoding is prop osed. Two-dimensional original data are encoded as a two-dimensional polari zation distribution. The polarization state at each pixel is scrambled by a mask that changes the polarization state into a random state. The mask can rotate the direction of the principal axes of the elliptically polarized l ight and can change the phase retardation at each pixel. The light with the random polarization state is stored as a hologram that can produce the vec tor phase-conjugate beam. In the decryption the vector phase-conjugation re adout can recover the original polarization state by use of the same mask u sed in the encryption. Experimental results of encryption and decryption wi th a bacteriorhodopsin film are presented. Society of America.