Cholesteric liquid crystal (CLC) cells were fabricated using three kinds of nematic liquid crystal (NLC) materials with different optical birefringent anisotropies Delta n. A larger Delta n of NLCs results in a larger photonic band gap (PBG) width and higher density of states (DOS) at the PBG edge for each CLC cell. We were able to lower the threshold energy by a factor of more than two using CLC cells with a broader PBG width.