Light controllable tuning and switching of lasing in chiral liquid crystals

A new approach based on the use of cholesteric liquid crystals (CLCs) and dye-doped light-sensitive chiral dopants was employed to create lasing materials with reversible tuning and switching. The lasing wavelength of optically-pumped dye-doped cholesteric liquid crystals ( CLCs) is shifted by irradiation with UV light. The shift depends on the UV light exposure. Lasing is switched off at high levels of UV light irradiation. A qualitative model describing different lasing regimes is proposed. (C) 2005 Optical Society of America.