Cholesteric liquid crystals are known to possess bandgap and exhibit strong reflection for one of two circular polarizations of light. We suggest a periodically twisted nematic liquid crystal as a medium, which possesses bandgap and exhibits strong reflection for any polarization of normally incident light. Two possible structures are considered: a sinusoidal modulation profile and a rectangular modulation profile. In both cases, the maximum bandgap of a periodically twisted structure is approximately twice as narrow as that of cholesterics. However, the polarization properties of these structures may make them more advantageous than cholesterics in a variety of applications.
© 2006 Optical Society of America
Original Manuscript: February 24, 2006
Revised Manuscript: March 7, 2006
Hakob Sarkissian, Boris Ya. Zeldovich, and Nelson V. Tabiryan, "Polarization-universal bandgap in periodically twisted nematics," Opt. Lett. 31, 1678-1680 (2006)