Lasing in Dye‐Doped Cholesteric Liquid Crystals: Two New Tuning Strategies

Tuning of a dye‐doped cholesteric liquid crystal mirrorless laser in the violet– ultraviolet wavelength range is achieved using two different strategies for controlling the periodicity of the cholesteric helical structures. Both methods are shown produce a shift of the lasing wavelength by 30–40 nm, and smooth variation of the helical pitch can be achieved (see Figure).