Mode competition of two bandedge lasing from dye doped cholesteric liquid crystal laser.

Mode competition of two-lasing modes at the photonic bandedge from dye-doped cholesteric liquid crystal lasing was studied by the alternation of temperatures. The increase or decrease of the wavelengths from photonic bandedges versus the alternation of temperature is attributed to the variation of helical twist power (HTP) and thus it shows the completely different result by choosing two of different nematic liquid crystals (MDA-981602 and MDA-3970). At certain temperature, the intensity contrast and slope efficiency between long and short emission lasing peaks were dominated from the experienced gain or loss of laser for the position of the photonic bandedge. By the linear combination of these two lasing modes with different emission wavelengths and intensity contrast at distinct temperature, the wide tuning of the output colors can be revealed from the CIE chromaticity diagram and thus it has opportunity to be used in the display technology in the near future.