Photochromic Optical Memory

具有杂环的二芳基乙烯经历了热不可逆和耐疲劳的光致变色反应。在这项研究中，我们的目标是开发使用光致变色二芳基乙烯的光致变色光学存储系统。本研究的重点是合成即使在大块晶相中也具有光致变色性质的新的二芳基乙烯，并揭示光致变色记忆所需的记录条件。我们还考察了光致变色近场光学记录的可能性。以2，4-二甲基、2，5-二甲基或2-甲基-5-苯基噻吩为基团的二芳基全氟环戊烯在晶相发生了可逆光致变色反应。用偏光显微镜测量了闭合环形态的吸收，证实了晶相的反应性。在偏振光下观察到通过旋转样品产生非常强烈的颜色变化。这是晶体中有色形态排列的明显证据。利用晶态光致变色化合物进行了近场光记录。首先用紫外光照射大块非晶薄膜(300 Nm)，然后用来自小吸管(100 Nm)的消光光漂白大块非晶薄膜。在薄膜中写入了小至80 nm的小标记。这些痕迹可以通过可见光照射来擦除。该系统的存储密度是现有光学存储系统的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20nW激光进行百万次读数。

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.