Phase Transitions in Nematic and Cholesteric Liquid Crystals

具有取向有序性但没有位置有序性的液晶有几种不同的形式，其中大多数是最近几年才发现的。其中包括一些非常奇特的结构，如在高光学活性的胆甾体中发现的立方晶格蓝相和无定形雾相，以及在某种肥皂溶液中首次发现的双轴向列相。它介绍了一系列旨在探索这些材料的相变的光学实验。他们的目标是有助于更好地理解具有张量序参数的系统所表现出的许多种类的临界现象，例如这些。

Liquid crystals which possess orientational ordering but no positional ordering come in several different forms, most of which have been discovered only in recent years. These include some rather exotic structures, such as the cubic lattice blue phases and the amorphous fog phase found in cholesterics of high optical activity, and the biaxial nematic first discovered in a certain soap solution. It presents a series of optical experiments designed to probe the phase transitions of these materials. Their goal is to contribute to a better understanding of the many varieties of critical phenomena exhibited by systems, such as these, having tensor order parameters.