Recently, amorphous organic photorefractive materials have generated great excitement because of their excellent performance, which permits applications in high-density holographic storage, real-time image processing, and phase conjugation. However, the heterostructure of the devices (consisting of glass cover slides, transparent electrodes, and the photorefractive material) and the tilted recording and readout geometry commonly used result in multiple reflected beams in addition to the normal object and reference beams. This result leads to several photorefractive gratings competing inside the photorefractive polymer device. We prove the coexistence of these gratings by two-beam coupling and four-wave mixing experiments and demonstrate how to distinguish between them.
[Optical Society of America ]
(090.0090) Holography : Holography
(160.4670) Materials : Optical materials
(160.5320) Materials : Photorefractive materials
(160.5470) Materials : Polymers
(260.0260) Physical optics : Physical optics
Klaus Meerholz, Erwin Mecher, Reinhard Bittner, and Yessica De Nardin, "Competing photorefractive gratings in organic thin-film devices," J. Opt. Soc. Am. B 15, 2114-2124 (1998)