Widely tunable ultraviolet-visible liquid crystal laser

Quasicontinuous tuning of a dye doped cholesteric liquid crystal (CLC) mirrorless laser in the ultraviolet-visible wavelength range is demonstrated using a single original device based on CLC as resonator and several resonant dyes. The thought is to combine the CLC pitch gradient and the distribution of different dyes. In the same cell, six dyes are combined in order to nearly cover the whole wavelength range from ultraviolet (370 nm) to red (680 nm). Some of the used dyes work as emitter, while others work in the Forster regime to decouple the excitation and emission processes. The relevant aspect of the device is that a simple translation of the cell respect to the same pump beam enables fine tuning of the laser wavelength in almost all the visible range, up to the ultraviolet. (C) 2005 American Institute of Physics.