Phototunable photonic bandgap in a chiral liquid crystal laser device

Abstract

This letter describes the phototunable photonic bandgap of cholesteric liquid crystal (CLC) doped with a fluorescent dye to generate the distributed feedback effect. Photoirradiation of the dye-doped CLC cell under UV light at 254 nm resulted in continuous changes in the chiral photonic bandgap from 550 to 720 nm due to photolysis reaction of the cholesteryl iodide embedded in the CLC host. We showed that the laser oscillation wavelength could be controlled in a wide wavelength range from 610 to 700 nm by photoassisted adjustment of CLC photonic bandgaps.