Light-scattering study of Fréedericksz transitions in nematic liquid crystals

P. Galatola

doi:doi:10.1051/jp2:1992247

Numéro		J. Phys. II France Volume 2, Numéro 11, November 1992


Page(s)		1995 - 2010
DOI		https://doi.org/10.1051/jp2:1992247

DOI: 10.1051/jp2:1992247
J. Phys. II France 2 (1992) 1995-2010

Light-scattering study of Fréedericksz transitions in nematic liquid crystals

P. Galatola

Dipartimento di Fisica, Politecnico di Torino, 10129 Torino, Italy, and Consorzio Interuniversitario Nazionale di Fisica della Materia, Unità di Torino Politecnico, Italy

(Received 30 December 1991, accepted in final form 5 August 1992)

Abstract
We introduce a novel technique to study the static distortion of a nematic liquid crystal in the neighbourhood of a Fréedericksz transition, based on the analysis of the power spectral density of quasi-elastic light-scattering. Under suitable conditions the symmetry breaking of the director profile due to the Fréedericksz transition induces a similar symmetry breaking in the angular dependence of the power spectral density, thus allowing a precise determination of the critical field. Experimental results are shown for the case of splay (twist) transition induced by an electric (magnetic) field. The correlation of the scattered fields at different angles is analyzed.