Rumi Mariacristina, White Timothy J, Bunning Timothy J
Opt Express. 2014 Jun 30;22(13):16510-9. doi: 10.1364/OE.22.016510.
We studied the appearance of second- and third-order Bragg reflections in cholesteric liquid crystals (CLCs) in cells where the electric field was perpendicular to the helical axis. Second-order reflections with reflectance values as large as 80% of the first-order one were observed in the gap regions of alignment cells with interdigitated electrodes for CLC mixtures with pitches in the range 0.5-1.0 μm upon application of a field. The characterization was enabled by local probing of the CLC using a microspectrophotometer. LC cells that are transparent in the visible spectrum in the off-state and become colored upon application of a field due the second- or third-order reflection band appearance were demonstrated. The spectral position of the higher-order Bragg reflections can also be tuned by adjusting the magnitude of the electric field.
我们研究了电场垂直于螺旋轴的盒中胆甾相液晶（CLC）中二阶和三阶布拉格反射的现象。对于间距在0.5 - 1.0μm范围内的CLC混合物，在施加电场时，在带有叉指电极的取向盒的间隙区域中观察到了反射率高达一阶反射80%的二阶反射。使用显微分光光度计对CLC进行局部探测实现了表征。展示了在关态下在可见光谱中透明且在施加电场时由于二阶或三阶反射带的出现而变色的液晶盒。高阶布拉格反射的光谱位置也可以通过调整电场强度来调节。
