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- Dahl, Ingolf, 1950
(författare)
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Ferroelectricity, SSFLC, bistability and all that
- 2002
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Ingår i: arXiv.org.
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- In the book “Ferroelectric and Antiferroelectric Liquid Crystals” by S. T. Lagerwall, the concept “polar liquid crystals” is proposed for the concept earlier known as “ferroelectric liquid crystals”, reserving the word “ferroelectric liquid crystals” for the case of “surface stabilization”. Thus Lagerwall in this way, by redefinition, becomes the coinventor of “ferroelectric liquid crystals”. The trouble is that a closer look on the invention reveals a state of bad logic and a total confusion. The concepts “polar”, “ferroelectric”, “hysteresis”, “SSFLC” and “bistability” are essential in the writing of Lagerwall, but these words are not used in a rigorous way. Also the pictorial evidence used by Lagerwall to illustrate the discovery of surface stabilized liquid crystals raises several questions. An alternative view of the physics of SSFLC cells is presented.
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| 2. |
- Lansåker, Pia, et al.
(författare)
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Spectral density analysis of thin gold films : Thickness and structure dependence of the optical properties
- 2013
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Ingår i: Proceedings. - Stockholm : The Electromagnetics Academy. - 0351-6067. ; , s. 443-447, s. 443-447
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we study the feasibility of representing the optical properties of ultrathin gold films by effective medium theories. Gold films with mass thicknesses in the range of 1.4 to 9.2 nm were deposited by DC magnetron sputtering onto non-heated glass substrates. Optical measurements in the range 0.25 to 2 µm were carried out by spectroscopic ellipsometry, and the effective complex dielectric function of each film was determined. The gold films were modelled as a mixture of gold and air, and a general effective medium description using the spectral density function (SDF) was used to describe their optical properties. Numerical inversion of the experimental dielectric function gave a broad and rather featureless SDF with a few superimposed peak structures, both for island structures and percolating films. The broad background is qualitatively similar to the predictions of the Bruggeman [Ann. Phys. (Leipzig), 5th series, 24 (1935) 636-679] model.
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