We report tunable single-mode lasing with an improved slope efficiency from a cholesteric liquid crystal (ChLC)
cavity with a three-layered structure. The device consists of one photopolymerized ChLC layer with a wide
reflection band, another ChLC layer with a notch reflection band and a Rhodamine-6G-doped ionic liquid layer
acting as the gain medium. Single-mode lasing can be obtained in this device structure because the ChLC layer with
the notch reflection band strongly reflects only one of the Fabry-Perot cavity modes. Tuning of the lasing
wavelength is achieved by tuning the reflection band of the notch ChLC. The device showed a maximum slope
efficiency of 16%, which was found to be approximately 1.5 times larger than that of ordinary ChLC lasers doped
with the pyrromethene 597 laser dye.