What is a nematic liquid crystal?
A nematic liquid crystal is one of several phases of liquid crystals and consists of rod shaped molecules which are aligned parallel to each other (approximately). In this configuration the molecules can “slide” with respect to their neighbors and can also rotate about their axis. Nematic liquid crystals also exhibit the least degree of positional order. When viewed under a cross-polarized optical microscope, a thread-like structure is seen. What is the reason for the grooves in the polyimide layer? The grooves serve as an alignment layer for the liquid crystal. The grooves on the two slides are made perpendicular to each other to allow for the necessary twisting of the liquid crystal between the two slides.This configuration, along with the crossed polarizers, is necessary to allow light to conform to this twist and emerge on the other side. Suppose one had two polarizers set up with their transmission axes perpendicular to each other. We now place a third polarizer at a 45 degree ang
