Random and distributed feedback laser action using spontaneous liquid crystal-liquid crystal nano-scale phase separation

本研究的目的是在胆甾相液晶-弯芯液晶二元体系中制备纳米级的相分离结构，并实现随机激光模式和分布反馈激光模式的结合。此外，金纳米粒子分散在该体系中，并结合表面等离子体效应。首先，通过小角X射线散射发现，胆甾相中的手性分子是宏观相分离的。为了克服这一问题，我们试图通过改变冷却速度等方法来寻找使纳米级相分离结构的最佳条件，但没有成功地制备出具有良好光子带隙的这种结构。对于相干后向散射测量系统，我们同时将脱碳硫醇修饰为金纳米粒子，并检查粒子是否聚集在向列相的低取向有序区。出乎意料的是，粒子聚集在较高取向有序区。另一方面，在本研究中，我们利用微流控装置制备了水包油(W/O/W)双乳状液。W/O/W乳状液的油相由CLC相组成。用二维成像光谱仪对溶解在水核区的一种染料的荧光发射光谱进行了空间映射，证实了CLC壳中的光子结构。文中还介绍了CLC壳层中奇怪的激光特性。

The purpose of this study is to fabricate the nano-scale phase separated structure in the cholesteric liquid crystal -bent-core liquid crystal binary system, and to attain the combination of random laser mode and distributed feedback laser mode. Furthermore, gold nanoparticles are dispersed in this system, and we aimed the combination with surface plasmonic effect.At first, it was found that chiral molecules contained in the cholesteric phase was macroscopically phase separated by small-angle X-ray scattering. To overcome this problem, we tried to find the best condition to make the nano-scale phase separated structure by changing the cooling rate etc, but it was not successful to fabricate the such a structure exhibiting the good photonic band. For the coherent back scattering measurement system, At the same time, we modified the decan-thiol to gold nano-particle, and check whether particles are accumulated in the lower orientational order region of nematic phase. Unexpectedly, the particles are accumulated in the higher orientational order region. Under the study, on the other hand, we fabricated the CLC shells as a wate-in-oil-in-water (W/O/W) double emulsion using a microfluidic device. The oil phase of the W/O/W emulsion is made up of a CLC phase. The photonic structure in the CLC shellis confirmed by the spatial mapping of fluorescence emission spectra of a dye dissolved in the aqueous core region with a two-dimensional imaging spectrometer. The curious lasing characteristics in the CLC shell are also presented.