Security wavelength multiplexing under a JTC scheme

DAFNE AMAYA; MYRIAN TEBALDI; ROBERTO TORROBA; NESTOR BOLOGNINI

Sidney (Australia)

Congreso; 20th Congress of the International Commission for Optics; 2008

International Comission of Optics

Optical field provides an environment for studies on information technologies for security and encryption systems and holographic memory systems. Typically, statistically independent random phase masks are important components of those methods. These studies, verify that the decryption performance is sensitive to the operation wavelength. The configuration of a joint transform correlator (JTC) where two-dimensional data and a key code are placed side-by-side at the input plane is one of the alternatives for optical security implementations. This optical setup is more compact than an ordinary holographic setup because the object and reference beams share a single optical system consisting of two Fourier-transforming lenses. Optics has many degrees of freedom (wavelength, polarization, three-dimensional topology, etc.). Some of these parameters are used in several papers for multiplexing data. Therefore, we propose in the present contribution the way to implement a wavelength multiplexing technique with a JTC architecture. In our JTC one window holds an input object and the other holds a random code mask used as reference. We have to remember that the different wavelengths introduce a re-scaling in the speckle patterns inherent to light propagation from random phase masks, thus generating the necessary different encrypting channels for every single input image. Consequently the input objects, encrypted with different wavelengths, are recorded one by one at the output plane producing the required multiplexing. We present computer simulations characterizing the method and confirming the performance of the proposed system.