Ternary phase-amplitude modulation with twisted nematic liquid crystal displays for Fourier-plane light homogenization in holographic data storage

László Domján, P. Koppa, Gábor Szarvas, Judit Reményi

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Holographic data storage applications often use liquid crystal displays as spatial light-amplitude modulators for writing data images. The hologram created in the Fourier plane is usually applied to store the information, since this plane supplies optimal data density. A well known technique for homogenizing the light distribution in the Fourier plane is the application of external random phase modulating masks. The requirement for pixel by pixel matched positioning of the phase modulating mask and the pixels of the spatial light-amplitude modulator is hard to solve in the optical systems and any positioning error leads to significant signal degradations. The article analyses the possibilities of realizing the required simultaneous amplitude and phase modulation of light with the application of a single LCD. Twisted nematic LCDs with different maximal birefringence are numerically investigated using the Jones matrix method. Elliptical incident and exit polarizations are proposed, by which ternary phase-amplitude modulation (+1,-1,0) can be realized. Test measurements are also presented that demonstrate the validity of the calculated results.

Original languageEnglish
Pages (from-to)382-390
Number of pages9
JournalOptik
Volume113
Issue number9
Publication statusPublished - 2002

Fingerprint

Amplitude modulation
Nematic liquid crystals
Phase modulation
data storage
homogenizing
Liquid crystal displays
phase modulation
liquid crystals
Data storage equipment
Pixels
pixels
Modulators
positioning
Masks
modulators
masks
Holograms
Birefringence
Optical systems
matrix methods

Keywords

  • Amplitude and phase modulation
  • Fourier holography
  • Holographic data storage
  • Ternary phase-amplitude modulation
  • Twisted nematic liquid crystal display

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Ternary phase-amplitude modulation with twisted nematic liquid crystal displays for Fourier-plane light homogenization in holographic data storage. / Domján, László; Koppa, P.; Szarvas, Gábor; Reményi, Judit.

In: Optik, Vol. 113, No. 9, 2002, p. 382-390.

Research output: Contribution to journalArticle

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