Flexoelectric polarisation effects in nematic liquid crystal phase gratings

C.L. Trabi, A.A.T. Smith, N.J. Mottram, C.V. Brown

Research output: Contribution to conferencePaper

1 Citation (Scopus)

Abstract

Nematic phase gratings have been studied in which a planar nematic layer of thickness 17.2 μm is sandwiched between two glass substrates coated with an alignment polymer. The upper substrate is a continuous earth plane and the lower substrate has a patterned electrode of interdigitated stripes (electrodes and gaps are both 40 μm wide). Reorientation of the nematic liquid crystal occurs in response to d.c. electric fields applied between the interdigitated electrodes. These nematic reorientation regions have been used to investigate the influence of the flexoelectric polarisation in the nematic liquid crystal by observing the resultant (i) movement of tilt fringes in a Mach-Zehnder interferometer, and (ii) optical diffraction patterns. In the Mach-Zehnder interferometer the periodic variation of the refractive index resulting from the periodic distortion profile is measured directly from the displacement of the tilt fringes. The asymmetry in the response to positive and negative polarities of the d.c. voltage for both measurement techniques is directly related to the sum of the flexoelectric coefficients, e1 + e3.
LanguageEnglish
PagesR500
Publication statusPublished - 2008
EventConference on Liquid Crystals XII - San Diego, CA
Duration: 11 Aug 200812 Aug 2008

Conference

ConferenceConference on Liquid Crystals XII
CitySan Diego, CA
Period11/08/0812/08/08

Fingerprint

gratings
Mach-Zehnder interferometers
retraining
electrodes
polarization
liquid crystals
crystals
periodic variations
polarity
diffraction patterns
alignment
asymmetry
refractivity
electric fields
glass
polymers
electric potential
coefficients
profiles

Keywords

  • flexoelectric polarisation
  • flexoelectric polarization
  • nematic phase gratings
  • liquid crystal
  • Mach-Zehnder interferometer
  • diffractive optical element

Cite this

Trabi, C. L., Smith, A. A. T., Mottram, N. J., & Brown, C. V. (2008). Flexoelectric polarisation effects in nematic liquid crystal phase gratings. R500. Paper presented at Conference on Liquid Crystals XII, San Diego, CA, .
Trabi, C.L. ; Smith, A.A.T. ; Mottram, N.J. ; Brown, C.V. / Flexoelectric polarisation effects in nematic liquid crystal phase gratings. Paper presented at Conference on Liquid Crystals XII, San Diego, CA, .
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keywords = "flexoelectric polarisation, flexoelectric polarization, nematic phase gratings, liquid crystal, Mach-Zehnder interferometer, diffractive optical element",
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year = "2008",
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note = "Conference on Liquid Crystals XII ; Conference date: 11-08-2008 Through 12-08-2008",

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Trabi, CL, Smith, AAT, Mottram, NJ & Brown, CV 2008, 'Flexoelectric polarisation effects in nematic liquid crystal phase gratings' Paper presented at Conference on Liquid Crystals XII, San Diego, CA, 11/08/08 - 12/08/08, pp. R500.

Flexoelectric polarisation effects in nematic liquid crystal phase gratings. / Trabi, C.L.; Smith, A.A.T.; Mottram, N.J.; Brown, C.V.

2008. R500 Paper presented at Conference on Liquid Crystals XII, San Diego, CA, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Flexoelectric polarisation effects in nematic liquid crystal phase gratings

AU - Trabi, C.L.

AU - Smith, A.A.T.

AU - Mottram, N.J.

AU - Brown, C.V.

PY - 2008

Y1 - 2008

N2 - Nematic phase gratings have been studied in which a planar nematic layer of thickness 17.2 μm is sandwiched between two glass substrates coated with an alignment polymer. The upper substrate is a continuous earth plane and the lower substrate has a patterned electrode of interdigitated stripes (electrodes and gaps are both 40 μm wide). Reorientation of the nematic liquid crystal occurs in response to d.c. electric fields applied between the interdigitated electrodes. These nematic reorientation regions have been used to investigate the influence of the flexoelectric polarisation in the nematic liquid crystal by observing the resultant (i) movement of tilt fringes in a Mach-Zehnder interferometer, and (ii) optical diffraction patterns. In the Mach-Zehnder interferometer the periodic variation of the refractive index resulting from the periodic distortion profile is measured directly from the displacement of the tilt fringes. The asymmetry in the response to positive and negative polarities of the d.c. voltage for both measurement techniques is directly related to the sum of the flexoelectric coefficients, e1 + e3.

AB - Nematic phase gratings have been studied in which a planar nematic layer of thickness 17.2 μm is sandwiched between two glass substrates coated with an alignment polymer. The upper substrate is a continuous earth plane and the lower substrate has a patterned electrode of interdigitated stripes (electrodes and gaps are both 40 μm wide). Reorientation of the nematic liquid crystal occurs in response to d.c. electric fields applied between the interdigitated electrodes. These nematic reorientation regions have been used to investigate the influence of the flexoelectric polarisation in the nematic liquid crystal by observing the resultant (i) movement of tilt fringes in a Mach-Zehnder interferometer, and (ii) optical diffraction patterns. In the Mach-Zehnder interferometer the periodic variation of the refractive index resulting from the periodic distortion profile is measured directly from the displacement of the tilt fringes. The asymmetry in the response to positive and negative polarities of the d.c. voltage for both measurement techniques is directly related to the sum of the flexoelectric coefficients, e1 + e3.

KW - flexoelectric polarisation

KW - flexoelectric polarization

KW - nematic phase gratings

KW - liquid crystal

KW - Mach-Zehnder interferometer

KW - diffractive optical element

UR - http://dx.doi.org/10.1117/12.794912

M3 - Paper

SP - R500

ER -

Trabi CL, Smith AAT, Mottram NJ, Brown CV. Flexoelectric polarisation effects in nematic liquid crystal phase gratings. 2008. Paper presented at Conference on Liquid Crystals XII, San Diego, CA, .