Abstract Temperature dependences of density, refractive indices, and dielectric constants have been measured for mesogenic compounds as some their cyano-analogues: . The effects substituting a phenyl ring by cyclohexyl ring, well –CN group an –NCS analyzed. results lead to the following conclusions: (i) above exchange rings leads mesogens long molecular axes which do not coincide with terminal groups, or –NCS; (ii) antiparallel correlation dipoles found cyano-mesogens does occur in case...

We report the synthesis of new laterally alkyl substituted high birefringent quaterphenyl and phenylethynyltolane liquid crystals with isothiocyanate terminal group. The thermal optical properties such as birefringence are measured discussed based on their molecular structures. compounds exhibit (Δn) in range 0.44–0.63, expected to be appropriate components nematic mixtures for various applications.

Abstract A new accurate and fast interference method for determining ordinary extraordinary refractive indices of nematic liquid crystals is presented discussed. The relies on microscopic measurements distances between fringes appearing in polarised parallel coherent monochromatic light beam transmitted normally to the surfaces through a wedge cell filled with nematic. Both glass plates confining are coated partly transparent thin film metal which deposited by evaporation vacuum. Owing...

MHPB(H)PBC and MHPB(F)PBC were studied by means of refractometric measurements. The refractive indices: n " (T), Á (T) I measured using combined methods, applying both appropriately prepared Abbe refractometer interference wedge. Values the for Sm A*, C* C A * phases are related to optical axis perpendicular proper smectic planes. results optic measurements discussed. Keywords: Antiferroelectric Liquid CrystalsRefractive IndicesOptical AxisOptical Indicatrix

Two series of unsymmetrical 4,4′-dialkylazoxy compounds: have been obtained, where K = C m H2m+l with 2 to 10. The method their synthesis and the results measurements phase transition temperatures, dielectric constants, refractive indices densities are presented. Compounds I in a lesser degree compounds II low-melting nematics small positive anisotropy constant. In both strong alteration was observed clearing point, constant Δε birefringence Δn number ofcarbon atoms alkyl radical.

The compounds from the fluorinated nF6B (n = 1,2,3,4,5,6,7) homologous series were investigated by means of optical, electrooptical, refractometrical, dielectric, densytometric, X-ray and IR spectroscopy methods. For some being a subject investigations computer simulation molecular properties done. In our opinion high value optical tilt Θo angle in comparison with obtained measurements can be interpreted terms de Vries model SmA* phases as well dimers creation process.

Abstract This paper presents tunable liquid crystal filter consists of three interference filters (LC – cells) with different cell thicknesses. These use nematic (with high birefringence). Such design allows to select precisely (using the electric field) wavelength outgoing light. Keywords: Interference filternematic crystaltunable Acknowledgments has been done in 2009 year under financial support Polish Ministry Sciences and Higher Education, Key Project POIG.01.03.01-14-016/08 "New...

Abstract A new method for quick and pretty accurate measurements of splay, twist bend elastic constants nematic liquid crystals is experimentally verified. The main concept relies on exploiting only the electric field determining magnitudes from threshold fields Freedericksz transitions in one hybrid in-plane-switched cell. In such cell deformations an investigated crystal are controlled by three separated pairs electrodes confining measurement domains. two them inter-digital mounted cover....

Abstract Liquid crystal cell (LCC) for space-borne laser rangefinder to space mission applications was developed, manufactured and tested under cooperation between Military University of Technology (MUT) in Poland Vavilov State Optical Institute (Vavilov SOI) Russia. LCC operates twisted nematic mode, commutating the polarization plane a beam working at 1.064 μm energy density not smaller than 0,15 J/cm2 pulse duration about 8 ns. The transmission is 95% aperture diameter less 15 mm....

Abstract Optical properties of a nematic liquid crystal with small refractive index and birefringence were studied. The ordinary extraordinary indices measured as functions temperature by using an Abbe refractometer wedge cells. From values these the orientational order parameter was calculated several methods corresponding mathematical models. Kuczyński et al. method found to be suitable for determining also materials featuring index, unknown density.

The homologous series of mesogenic (S)-4″[n-(perfluoroalkanoyloxy)hexyl-1-oxy]-4-(1-metylheptyloxy-carbonyl)terphenyl compounds exhibiting low temperature, wide range, near orthoconic antiferroelectric phase has been synthesized [1 Kula, P., Dabrowski, R., Kenig, K. and Chyczewska, D. 2006. New from chiral terphenyls. Ferroelectrics, 343: 19–26. [Taylor & Francis Online], [Web Science ®] , [Google Scholar]]. Compounds the differ each other by a position single fluorine atom substituted at...

The promising materials for applications are Antiferroelectric Liquid Crystals. Two dielectric modes were detected in AFLCs, as far [1 Lagerwall, S. T. 1999. Ferroelectric and Crystals, Wiley-VCH. [Crossref] , [Google Scholar], 2 Haase, W. 2003. St. Wróbel, Relaxation Phenomena, Springer-Verlag. Scholar]]. Low frequency mode called P L with the relaxation around 100 Hz well high H kHz. first (P ) is related to in-phase motions of molecules on cone surface (when two neighbouring layers taken...

There exists a problem in diagnostics of dense plasma (so-called Thomson diagnostics). For this purpose, the is illuminated by series high energy laser pulses. Such pulses are generated several independent lasers operating sequentially, and these to be directed along an exactly same optical path. In case, each separate pulse as large 3 J, so it impossible generate burst such single laser. situation, have used. To form path with λ = 1.064 μm absolute value through special refractive index...

W-1000 orthoconic antiferroelectric liquid crystal eutectic mixture was prepared in Military University of Technology. This is probably the broadest mixture, ever prepared. Precise dielectric measurements were performed a broad temperature range. Some parameters detected modes and their characteristics are found. It seems that different regions numbers should be anticipated to fit experimental results. Results discussed with respect theoretical model.

ABSTRACTMethods of 3D imaging present on the market can be divided into two basic groups: autostereoscopic and stereoscopic. At stereoscopic methods it is necessary to use special glasses for separation images constituting stereo-pair. The most commonly used active consist electro-optical transducers based twisted nematic or other effects. Here evaluation liquid crystal mixtures designed intentionally in order eliminate drawbacks available contemporary market. Material parameters new such...

Abstract Recently the investigation in field of display technology has been boosted by availability new materials. The mostly promised solution for that looks to be based on an antiferroelectric liquid crystalline materials (AFLC). group consisting a fluorinated terminal chain recently synthesized Poland [1]. Such key factors as optical indices, apparent tilt angle, and structural properties electrooptical performance these have studied. effect bend (hockey stick like) molecular shape...

Abstract Two investigated antiferroelectric liquid crystals, MHPB(H)PBC and MHPB(F)PBC, were synthesized [1] some their physical properties described earlier [2]. Apart of the above, MHPB(F)PBC have been studied by means dielectric, densitometric, refractometric X-ray measurements. Spontaneous polarization P s tilt angle θ in ferro- (SmC*) (SmCA*) phases also investigated. Transverse α1 longitudinal molecular polarizabilities calculated from ordinary n 0 extraordinary e refractive indices...

A short review of liquid crystal compounds with a low birefringence and ordinary refractive index is presented. Special attention given to alkylcyclohexylalkyl carbonates, which belong family LCs having high clearing point temperatures, viscosity, no as 1.442. Examples multicomponent mixtures positive negative dielectric anisotropy are described. © 2005 Optical Society America

Wedge cell lled with a homogeneously oriented nematic liquid crystal was exploited as an interference wedge to measuring indices of refraction.Interference fringes from the were observed in polarised light reection or transmission mode polarisation microscope determining ordinary and extraordinary refraction birefringence (i.e.anisotropy both indices).The close apex uniform could be well described two-beam approximation.The refractive computed using simple formulae involving only distances...

Abstract There exists the problem in diagnostics of dense plasma (so-called Thomson diagnostics). For this purpose is illuminated by series high energy laser pulses. The each separate pulse as large 3 J, so it impossible to generate a burst such pulses single laser. In situation, are generated several independent lasers operating sequentially, and these be directed along same optical path. To form an path with λ = 1.064 μm absolute value special refractive index matched twisted Nematic...

Polarization phenomena in an elliptical liquid crystal-core fiber at third optical window, i.e., close to 1550 nm have been investigated. This includes direct measurement of polarization mode dispersion and the beat-length parameter. The contained a nematic mixture characterized by extremely low values refractive indices.

Two smectogens being structural analogs with the opposite space orientation of COO ester group in molecular core exhibit extremely different tilt angles. A mechanism induction high optical angle is searched on basis extensive investigations those compounds. Computer modeling molecules and physical parameters smectic phases were done. Different aggregates forming observed. The size shape are estimated measurements calculations. values angles studied compounds discussed.

Wedge cells of small apex angle, filled with liquid crystals, were used to determining optical characteristics as functions temperature for three crystalline mixtures recently produced and a reference nematic. The interference fringes appearing in polarised monochromatic light (of sodium yellow line) normally incident on the cell exploited measure ordinary extraordinary refractive indices reflection mode birefringence transmission mode. measurements repeated using Abbe's refractometer 6CHBT...

An efficient, quick and pretty accurate interference method for determining dispersions of ordinary n o extraordinary e refractive indices optical anisotropy nematic liquid crystals, i.e., ne(λ), no(λ) Δn(λ) ≡ (λ)–no(λ), as functions wavelength λ (in visible near infrared region), is presented. The relies on measurements positions fringes in spectrogram produced by a flat-parallel crystal cell only one run.