Organic photorefractive materials

About: Organic photorefractive materials is a research topic. Over the lifetime, 697 publications have been published within this topic receiving 13041 citations.

Highly efficient photorefractive composites based on layered photoconductive polymers

Abstract: High-performance photorefractive materials based on the layered photoconductive polymers PPT-CZ [rigid backbone of poly(p-phenyleneterephthalate) with pendent carbazole groups] are studied. The composites are composed of PPT-CZ and are doped with the sensitizer C60 and nonlinear optical chromophores. Despite the absence of a plasticizer and the lower concentration of the carbazole photoconductive moieties as compared with poly(N-vinyl carbazole), these materials show high photorefractive sensitivity, i.e., Sn2 of 70± 7 cm2/kJ at E0=100 V/μm for PPT-CZ(n=12):diethylaminodicyanostyrene:C60. The low glass transition temperature (<0°C) leads to a high rotational mobility of the chromophores that results in large refractive-index changes. For all the composites that were investigated, the two-wave mixing gain Γ exceeds 100 cm-1 at an applied field of 50 V/μm.

Tracking novelty filter at 780 nm based on a photorefractive polymer in a two-beam coupling geometry.

Abstract: We have constructed an all-optical tracking novelty filter based on the dynamic holographic properties of an efficient and fast infrared-sensitive photorefractive polymer. The photorefractive polymer was used in a two-beam coupling geometry. The polymer had a gain coefficient of 175 cm-1 at a wavelength of 780 nm and an applied field of 72 V/µm. In contrast to what has been observed in photorefractive crystals, the gain coefficient and the filter contrast are largely independent of the writing beam’s intensity ratio. We show images of a swinging pendulum observed through the novelty filter.

Solution of nonlinear equations for four-wave interactions in photorefractive media

Abstract: A system of nonlinear equations is solved to describe a four-wave interaction in photorefractive media generating transmission or reflection refractive index gratings in the case of a drift-diffusive nonlinearity mechanism with an arbitrary complex coupling constant. An analysis is made of the four-wave interaction in the geometry of a nonlinear ring resonator where a reflection grating is formed.

Method for spectral filtering of optical radiation

Abstract: The present invention provides a device and method of spectral filtration of optical radiation by forming a holographic diffraction grating in a photorefractive medium. The photorefractive medium can be a crystal, a polymer or any other material with suitable photorefractive properties. The wavelength of the filtered radiation can be selected depending on the electrooptical properties of the photorefractive material, by applying an electric field and, in addition, by sufficiently high transfer function parameters achieved due to a high diffraction efficiency of the grating can be obtained. According to the invention, the method for spectral filtering of optical radiation based on diffraction from a holographic diffraction grating comprises forming the grating in a photorefractive material by directing two coherent light beams onto a face of the photorefractive material at some angle, intersecting two coherent light beams inside the material and directing a radiation beam onto the photorefractive material preferably along the diffraction grating wave vector. The direction of the grating wave vector in the described system is not parallel to the directions of propagation of the two coherent light beams.