Static alignment states in a bistable azimuthal nematic device with blazed grating sidewalls

C R Evans (1) , a J Davidson (2) , C V Brown (1) , N J Mottram (2)

1 School of Science and Technology
2 Department of Mathematics and Statistics [Univ Strathclyde]

Static alignment states in a bistable azimuthal nematic device with blazed grating sidewalls. Abstract Bistable azimuthal alignment has been produced in channels of homogeneous nematic liquid crystal with periodic grating sidewalls. The grating morphologies included a symmetric triangular profile (blaze/pitch (b/p) = 0), an asymmetric highly blazed sawtooth profile (b/p = 0.5), and profiles with different amounts of blaze asymmetry between these two extremes. The observed optical textures and the trend in the relative frequency of occurrence of the two stable states as a function of the asymmetry were in agreement with the predictions of n-director based Frank-Oseen nematic continuum theory. A sidewall grating morphology with an intermediate degree of blaze asymmetry, b/p = 0.3, gave the highest optical contrast between the bistable states.

Mots clés: Nematic liquid crystals; bistable states; polarisation; birefringence PACS keywords 42. Optics; 42.25.Ja Polarization; 42.25.Lc Birefringence; 42.70.Df Liquid crystals; 42.79.Kr Display devices; liquid-crystal devices; 77. Dielectrics etc; 77.84.Nh Liquids; emulsions; and suspensions; liquid crystals

C R Evans, a J Davidson, C V Brown, N J Mottram. Static alignment states in a bistable azimuthal nematic device with blazed grating sidewalls. Journal of Physics D: Applied Physics, 2010, 43 (49), pp.495105. ⟨10.1088/0022-3727/43/49/495105⟩. ⟨hal-00597841⟩