Photonic Density of States of a Stack of Cholesteric Liquid Crystal and Isotropic Medium Layers

We calculated the photonic density of states (PDS) of the eigen polarizations in the system composed of a stack of layers of a cholesteric liquid crystal and an isotropic medium. The reflection spectra and PDS peculiarities, as well as the peculiarities of absorption and emittance were investigated. We obtained the dependences of the PDS as a function of parameters characterizing absorption and gain. It was shown that the subject system can be used in lasers for obtaining low threshold lasers with the emittance wavelength tunable in wide ranges. The system also can work as a multi-position trigger.