PMMA/PQ感光高分子材料的製備與特性研究及其在光資訊儲存上的應用

Abstract

本論文嘗試研製高光學品質的感光高分子材料，並探討其中的反應機制及其對全像資訊儲存的影響，最後將其應用至全像資訊儲存系統中。 在高分子材料製程方面，首先，我們製作出合適於填充樣品的玻璃容器，再以染料PQ (9,10-phenanthrenequinone)及啟始劑AIBN (Azobisisobutyronitrile)摻合入純化的MMA (Methyl methacrylate)單體中，裝入事先製做完成的容器內。經由不同反應條件，最後以45℃、反應3天為標準製程，製作出不同組成濃度及厚度的PMMA/PQ感光高分子材料。 在材料的反應機制分析方面，經由UV、TGA、GPC、Mass、FT-IR、NMR的分析，我們得到PQ是與單體MMA反應形成兩種可能的加成物，並且為PMMA/PQ的光學儲存機制建立合理的模型。由於樣品的組成會對其光學性質有所影響，實驗結果我們得到PQ的比例愈高，其繞射效率愈佳；AIBN的比例愈高，其繞射效率稍微增加，但是光學品質變差。綜合這些研究心得，我們可以把PMMA/PQ做到厚度2.5cm，且得到良好的光學品質。 在全像資訊儲存方面，結果顯示儲存動態範圍隨厚度的增加而變大，但是響應時間卻也同時隨厚度的增加而變長；角度選擇性則隨著厚度的增加而變小。然後，我們利用曝光時程的計算，改善了每張儲存影像的繞射效率均勻性。再以這種特殊的曝光時程，利用垂直的角度多工方法將250張影像儲存在1cm3的樣品中，最後得到高重建品質的儲存效果。

In this thesis, we synthesize a high optical quality photopolymer for holographic memory. Chemical analyses are performed to study on the recording mechanism. Based on these results, characteristics for holographic data storage are obtained. Then, a volume holographic storage system is constructed using our polymer block. Our samples are prepared by dissolving 9,10-phenenthrenequinone (PQ, up to 0.7%) and initiator azobisisobutyronitrile (AIBN, up to 1.5%) in the purified Methyl methacrylate (MMA) monomer. The solution is poured into different glass flasks to fabricate the samples in a variety of dimensions. The samples with different concentration of AIBN and PQ are then placed in a temperature-controlled chamber at 45℃ for three days to polymerize MMA monomer. Then, the samples are turned into solid blocks. Analyzing of the optical exposed samples by using UV, TGA, GPC, Mass, FT-IR and NMR indicates that in our PMMA/PQ samples, the PQ molecules reacted with MMA monomers one by one. The products contain two different compounds. We have also studies the influence of the concentrations of PQ and AIBN for the holographic recording. The results show that the diffraction efficiency of the grating increases with the concentration of PQ, and increases slightly as that of AIBN increases. However, the increase of the AIBN will reduce the optical transmission of the samples. Based on these results, up to 2.5x2.5x2.5 cm3 PMMA/PQ photopolymer volume with high-optical-quality can be made. We have performed multiple plane wave holograms storage experiments in our PMMA/PQ photopolymer samples to study photo-sensitivity, dynamic range, angular selectivity, exposure schedule and fanning effect. The results show that the dynamic range and the response energy of our polymer increase with the thickness. The angular selectivity decreases with the thickness. In addition, a special exposure schedule is proposed to obtain uniform diffraction efficiency of multiple holograms. Finally, multiple storage of 250 image holograms recorded in a single spot of a 1cm3 sample block using scheduled exposure and 90-degree angle-multiplexing geometry is demonstrated.