title: Thermal optical non-linearity of nematic mesophase enhanced by gold nanoparticles--an experimental and numerical investigation.
abstract: In this work the mechanisms leading to the enhancement of optical nonlinearity of nematic liquid crystalline material through localized heating by doping the liquid crystals (LCs) with gold nanoparticles (GNPs) are investigated. We present some experimental and theoretical results on the effect of voltage and nanoparticle concentration on the nonlinear response of GNP-LC suspensions. The optical nonlinearity of these systems is characterized by diffraction measurements and the second order nonlinear refractive index, n2, is used to compare systems with different configurations and operating conditions. A theoretical model based on heat diffusion that takes into account the intensity and finite size of the incident beam, the nanoparticle concentration dependent absorbance of GNP doped LC systems and the presence of bounding substrates is developed and validated. We use the model to discuss the possibilities of further enhancing the optical nonlinearity.
authors.affiliation: Institute of Physics of National Academy of Sciences of Ukraine, Kyiv 03028, Ukraine.
authors.forename: O
authors.initials: O
authors.lastname: Kurochkin
authors.affiliation: School of Mathematics, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Y K
authors.initials: YK
authors.lastname: Murugesan
authors.affiliation: School of Mathematics, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: T P
authors.initials: TP
authors.lastname: Bennett
authors.affiliation: School of Mathematics, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: G
authors.initials: G
authors.lastname: D'Alessandro
authors.affiliation: Institute of Physics of National Academy of Sciences of Ukraine, Kyiv 03028, Ukraine.
authors.forename: Y
authors.initials: Y
authors.lastname: Reznikov
authors.affiliation: Department of Chemistry, University of Hull, Hull, HU6 7RX, UK.
authors.forename: B J
authors.initials: BJ
authors.lastname: Tang
authors.affiliation: Department of Chemistry, University of Hull, Hull, HU6 7RX, UK.
authors.forename: G H
authors.initials: GH
authors.lastname: Mehl
authors.affiliation: School of Physics, University of Southampton, Southampton, SO17 1BJ, UK. mfk@soton.ac.uk.
authors.forename: M
authors.initials: M
authors.lastname: Kaczmarek