DAMMANN GRATINGS FOR MULTISPOT ARRAY GENERATION BY USING PHOTOINDUCED ANISOTROPIC MATERIALS

The binary phase Dammann gratings are promising optical fan-out elements for applications to lightwave communications and digital optical computing systems. We present a simple technique for fabricating the Dammann gratings and demonstrate 9 x 9 array generation utilizing the property of the photoinduced anisotropy of amorphous chalcogenide semiconductor thin films. The principles of Dammann gratings in conjunction with the photoinduced anisotropy, which is described in terms of third-order nonlinear polarization, are presented. Experimental results show that photoanisotropic amorphous As2S3 thin film is capable of generating a binary (0, pi) phase gratings.