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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 15, Iss. 16 — Aug. 6, 2007
  • pp: 10381–10389

Characterization of a nematic PALC at large oblique incidence angles

C. C. Tsai, H. C. Wei, C. H. Hsieh, L. P. Yu, C. R. Yu, H. S. Huang, and C. Chou  »View Author Affiliations

Optics Express, Vol. 15, Issue 16, pp. 10381-10389 (2007)

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Compared with conventional photometric methods of measuring cell parameters, including the cell gap and the pretilt angle of a nematic parallel-aligned liquid crystal (PALC) using multiple wavelengths at normal incidence, this research proposes the use of a phase-sensitive interferometric ellipsometer to determine cell parameters precisely based on a single wavelength at large oblique incidence angles. The advantage of this method is that it detects the phase difference using an optical heterodyne interferometer in which a common phase noise rejection mode is provided. Thus, there is a high signal-to-noise ratio (SNR) on the phase measurement. In addition, a range of large oblique incidence angles on the PALC is used so that a high sensitivity measurement of the cell parameters is obtained experimentally. During the measurements, the multiple reflections and spatial shifting effect of the emerging extraordinary ray (E-ray) and ordinary ray (O-ray) from the PALC at large oblique incidence angles are able to be reduced effectively by the use of retro-reflected geometry in the interferometer. The experimental results verify that the sensitivities for the cell gap and pretilt angle measurements are 0.3 nm and 0.01°, respectively.

© 2007 Optical Society of America

OCIS Codes
(040.2840) Detectors : Heterodyne
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
(120.5410) Instrumentation, measurement, and metrology : Polarimetry

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: May 11, 2007
Revised Manuscript: July 16, 2007
Manuscript Accepted: July 18, 2007
Published: August 2, 2007

C. C. Tsai, H. C. Wei, C. H. Hsieh, L. P. Yu, C. R. Yu, H. S. Huang, and C. Chou, "Characterization of a nematic PALC at large oblique incidence angles," Opt. Express 15, 10381-10389 (2007)

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