Development and Evaluation of Transparent Photonic Materials for Photochemically-induced Large Refractive-index Change

今年，我们可以实现本项目的目标，涉及以下三个主题1。利用光异构化和光消除反应控制聚合物薄膜的折射率。制备了含有苯甲酰基、苯并呋喃、苯并苯和/或三氟甲基降冰片双烯衍生物的薄膜，并用m线技术测量了它们在光照射前后的折射率。薄膜的折射率变化最大达到-0.066，这是迄今为止透明聚合物薄膜折射率变化的冠军数据。含苯肼基团的PMMA薄膜的折射率也得到了提高。近场扫描光学显微镜(NSOM)纳米折射率图样的形成和观察。去年，我们首次实现了折射率图案化，使用NSOM制作了一种含有降冰片二烯衍生物的PMMA薄膜。今年，我们研究了图案化的光强对表面形貌的影响，对于一种新的聚合物TBFNBD薄膜，我们也可以观察到没有吸收和表面没有凹陷的折射率图案化。圆偏振光(CPL)对液晶织构的光学控制。在典型的向列型液晶中掺入含丁基乙酰丙酮配体的铬配合物，并用633 nm He-Ne激光照射CPL，实现了CPL对液晶织构的纳米-胆甾型可逆控制。

In this year, we could realize the purpose of the present project concerning the following three topics.1. Refractive index control of polymer films by using photoisomcrization and photoelimination Reactions. Films containing norbormadiene derivatives with anisyl, benzofuryl, thiophenyl, and/or trifluoromethyl groups were prepared and their refractive indices were measured before and after photoirradiation with an m-line technique. The refractive index changes of the films reached -0.066 in maximum, which is a champion datum so far for the refractive index change in transparent polymer films. Refractive index increase was also realized for PMMA films containing phenylazide groups.2. Formation and observation of nano-refractive-index patterns by near-filed scanning optical microscope (NSOM). Last year we realized for the first time a refractive-index pattering by using NSOM for a PMMA film containing a norbornadien derivative. This year, the effects of light intensity of patterning on the surface morphology was studied, and we could observe refractive index patterning with no absorption and without concave of the surface also for a new poly TBFNBD film.3. Chirooptical control of liquid-crystalline texture by circular polarized light (CPL). Namatic-cholesteric reversible control of a liquid-crystalline texture by CPL was realized by doping chromium complex with butylacetylacetonate ligands into a typical nematic liquid crystal and by irradiating it with CPL from 633 nm He-Ne laser.