Cylindrical fiber cored by a blue phase liquid crystal

We consider an electromagnetic field propagating within a cylindrical waveguide whose core consists of a material in which the elongated molecules have the tendency to rotate helically along all directions perpendicular to a given vector which we chose to be along the axis of the fiber. This type of structure can be found in some chiral nematic materials such as blue phases. We establish the electromagnetic equations governing the dynamics of all the orders of propagating modes and solve them numerically. We found the band structure of the mentioned modes and show that they can be classified in quasi-transverse magnetic and electric modes whose corresponding cut-off frequencies are in some cases degenerated. Also, the profile field amplitudes versus the radial axis of the fiber are depicted and analyzed. Finally, we discuss how the modes are conformed and their conditions to propagate electromagnetic waves. (paper)