Self-imaging by a Photorefractive Volume Phase Grating

G. FORTE; A. LENCINA; M. TEBALDI; N. BOLOGNINI

Bogotá

Seminario; Pan American Advanced Studies Institute on Frontiers in Imaging Science; 2011

Pan American Advanced Studies Institute

In our proposal a light intensity distribution generated by an incoherently illuminated amplitude planar grating is projected in a photorefractive crystal. This 3D distribution is mapped into an index refractive perturbation via the photorefractive effect thereby generating a volume phase grating. The self-imaging phenomenon through this photorefractive volume phase grating coherently illuminated is theoretically and experimentally analyzed. A model to simulate the volume grating that considers the 3D light intensity distribution formed in the crystal [1] combined with the theory of photorefractive volume grating formation [2] is proposed. A path-integral approach to take into account the inhomogeneous propagation through the photorefractive grating to explain self-image patterns is employed [3]. The experimental and theoretical results show that the self-images location coincides with that of the self-images generated by planar phase grating of the same period. The self-images visibility depends on three grating parameters: the output pupil diameter of the grating recording optical system, the external electric field applied on the crystal and the crystal thickness. Moreover, a sinusoidal dependence of the self-image visibility in terms of a proposed phase parameter is found. A good agreement between theoretical and experimental results is observed. [1] J.W. Goodman, Introduction to Fourier Optics, Sec.6.4., McGraw-Hill, Inc. New York, 1968.[2] P. Yeh, Introduction to Photorefractive non linear Optics, John Wiley & Sons Inc., New York, 1993.[3] G. Forte, A. Lencina, M. Tebaldi, N. Bolognini, Opt. Commun. 284 (2011) 2494.