Organic Photorefractive Materials and Applications

Abstract

This review describes recent advances and applications in the field of organic photorefractive materials, an interesting area in the field of organic electronics and promising candidate for various aspects of photonic applications. We describe the current state of knowledge about the processes involved in the formation of photorefractive gratings in organic materials and focus on the chemical and photo‐physical aspects of the material structures employed in low glass‐transition temperature amorphous composites and organic photorefractive glasses. State‐of‐the art materials are highlighted and recent demonstrations of photonic applications relying on the reversible holographic nature of the photorefractive materials are discussed.

Refractive Properties of the Bio- And Nano-Structured Materials as an Indicator of the Model Matrix Macro Parameters Modification

“…15. It should be remarked, that at present time different scientific groups have studied the organic photorefractive materials and have found the extended area of their application in the technique and biomedicine [18], [19]. But, it should be mentioned, that basically the authors have drawn the attention on the structuring process influence on the volume of the organics.…”

Molecular design of photorefractive polymers

“…86 Polarizability anisotropy Δα, the ground-state dipole moment μ and the first hyperpolarizability β are significantly affected by structural modifications due to changes in the electron-donating and -accepting substituent groups. The two terms of FOM of the NLO chromophores with various π-conjugated structures with different electron-donating and -accepting substituent groups were individually evaluated as a function of the resonance parameter c 2 for two basic resonance states of push-pull chromophores, a neutral polyene limit (D-A, c 2 = 0), cyanine limit with c 2 = 0.5, zwitterionic limit (betaine type, D + -A − , c 2 = 1) 26,86,87 and as a function of π-bond-order alternations (BOAs). 27,88,89 For π-conjugated molecules with single-double bond series, bondlength alternation (BLA) is defined in terms of the difference between the average lengths of single bonds and that of double bonds, which is significantly related to the optimized geometries.…”

“…Namely, the contribution of the hyperpolarizability term due to the electro-optic effect (Pockels effect) was far outweighed by the contribution of the linear polarization term due to the birefringence of the NLO molecule by the space-charge field (molecular orientation enhancement). 26,27,[86][87][88][89] Beyond the cyanine limit (c 2 40.5, BOA40), some problems have been noted: 26,87 high-melting crystalline solids are generated, which lead to difficulties of dissolving the materials in rather non-polar polymeric matrices. Then, the molecular design around cyanine limits offers better NLO chromophores for enhanced PR performance.…”

“…Over the past two decades, many featured review articles [16][17][18][19][20][21][22][23][24][25][26][27] and book chapters [28][29][30][31][32][33][34][35] have been published, which have given us a technical understanding, and have provided researchers in the field with a direction for the development of relevant applications. The latest comprehensive review on PR polymer composites was reported in 2011, 26 and a review on its applications for holography was published in 2014. 27 This review highlights the current state-of-the-art research on organic PR polymer composites with a specific focus on the response speeds (inverse of response time) of PR optical diffraction and amplification processes.…”

“…In 1994, 15 a high diffraction efficiency of 86% (the remaining 14% was attributed to optical losses) and a large optical gain exceeding 200 cm À1 was reported in photoconductive PVK-based PR composites. Over the past two decades, many featured review articles [16][17][18][19][20][21][22][23][24][25][26][27] and book …”