Dual frequency switchable cholesteric liquid crystal light shutter and driving waveform

A liquid crystal shutter, comprising:

• a cholesteric liquid crystal material disposed between first and second substrates comprising a first layer having a first twist sense and a second layer having a second twist sense opposite said first twist sense, wherein a third substrate is interposed between said first and second substrates to separate said first and second layers;
• and
• means for simultaneously addressing said first and second layers with at least two distinct ranges of frequency of an electric filed, wherein application of a low range of frequency between said first and third substrates and between said second and third substrates causes said layers to exhibit a positive dielectric anisotropy and wherein application of a high range of frequency between said first and third substrates and between said second and third substrates causes said layers to exhibit a negative dielectric anisotropy, wherein said negative dielectric anisotropy causes said material to be switched to a state which reflects both right and left circularly polarized light incident thereto within a predetermined spectrum of light while allowing remaining spectrums of light to be transmitted through said substrates, and wherein said positive dielectric anisotropy causes said material to be switched to a state which is transparent.