Position-sensitive cholesteric liquid crystal dye laser covering a full visible range

We fabricated a cholesteric-liquid-crystal distributed-feedback laser cell with spatial gradient structures not only of the helical pitch but also of the concentrations of two dyes. By utilizing the energy transfer between two dyes, lasing was achieved covering a full visible range from 470 to 670 nm continuously by translating the cell with respect to a pumping beam without changing the excitation wavelength.