  Some properties of defect modes of cholesteric liquid crystals (CLC) are
presented. It is shown that when the CLC layer is thin the density of states
and emission intensity are maximum for the defect mode, whereas when the CLC
layer is thick, these peaks are observed at the edges of the photonic band gap.
Similarly, when the gain is low, the density of states and emission intensity
are maximum for the defect mode, whereas at high gains these peaks are also
observed at the edges of the photonic band gap. The possibilities of
low-threshold lasing and obtaining high-Q microcavities have been investigated.
