Photochromic Optical Memory

具有杂环的二芳基乙烯经历热不可逆和抗疲劳的光致变色反应。在本研究中，我们的目的是开发光致变色的光存储系统使用的光致变色二芳基乙烯。本论文的主要工作是合成新型的二芳基乙烯类化合物，这些化合物在体相结晶状态下也表现出光致变色性，并揭示光致变色记忆所需的记录条件。以2，4-二甲基-，2，5-二甲基-，2-甲基-5-苯基噻吩为芳基的二芳基全氟环戊烯在晶相中发生可逆的光致变色反应。通过用偏光显微镜测量闭环形式的吸收来确认结晶相中的反应性。在偏振光下观察到通过旋转样品的非常强烈的颜色变化。这是晶体中有色形式排列的明显证据。利用该晶体光致变色化合物进行了近场光记录。首先用UV光照射大块非晶膜（300 nm），然后用来自小微量移液管（100 nm）的渐逝光漂白小斑点。在膜中写入小至80 nm的小标记。这些痕迹可以用可见光照射消除。该系统的存储密度是现有光存储系统的100倍，并对超低功率激光无损读出和光致变色化合物超分辨进行了研究。使用20 nw激光进行百万次读出。

Diarylethenes having heterocyclic rings undergo thermally irreversible and fatigue resistant photochromic reactions. In this research we aimed at developing photochromic optical memory systems using the photochromic diarylethenes. The research was focused to synthesize new diarylethenes, which show photochromism even in the bulk crystalline phase, and to reveal necessary recording conditions for the photochromic memory. We also examined the possibility of photochromic near-field optical recording.Diarylperfluorocyclopentenes having 2,4-dimethyl-, 2,5-dimethyl-, or 2-methyl-5-phenylthiophenes as the aryl groups underwent reversible photochromic reactions in the crystalline phase. The reactivity in the crystalline phase was confirmed by measuring the absorption of the closed-ring forms with a polarizing microscope. A very strong color change by rotating the sample was observed under the polarized light. This is clear evidence of alignment of the colored forms in the crystal. The near-field optical recording using the crystalline photochromic compounds was carried out. Initially the bulk amorphous film (300nm) was irradiated with UV light, and then a small spot was bleached by evanescent light from a small micropipette (100nm). Small marks as small as 80 nm were written in the film. The marks could be erased by irradiation with visible light. This system has 100 times larger memory density compared to current optical memory systems.Non-destructive readout using super-low power laser light and super-resolution using photochromic compounds were also examined. Million times readout using 20 nw laser was performed.