Role of optical extinction in holographic polymer-dispersed liquid crystals

Autor(en)

Mostafa Ellabban, Martin Bichler, Martin Fally, Irena Drevensek-Olenik

Abstrakt

The origin of optical diffraction in holographic polymer-dispersed liquid crystal (H-PDLC) transmission gratings was investigated by optical two beam-coupling analysis based on the linear phase-shift technique. Gratings with the pitch of 1micrometer and the thickness of 50 micrometers were fabricated from a UV curable mixture of commercially available constituents. Photopolymerization in the interference field of two laser beams produces not only a periodic variation of the refractive index, but also a periodic modulation of optical extinction due to light scattering. Both of them contribute to the diffraction efficiency of the gratings. The magnitudes and relative phases of the two contributions were measured as a function of a recording time of the grating and as a function of an applied external electric field. During the initial stage of the grating formation phase modulation is predominant, while at longer exposures both contributions have the same order of magnitude. They are phase shifted with respect to each other for around pi/2. Application of an external electric field causes a strong decrease of the amplitude modulation, while phase modulation is much less perturbed.

Organisation(en)

Physik Funktioneller Materialien

Externe Organisation(en)

University of Ljubljana

Journal

Proceedings of SPIE

Band

6587

Seiten

1-8

Anzahl der Seiten

8

ISSN

0277-786X

DOI

https://doi.org/10.1117/12.723361

Publikationsdatum

2007

Peer-reviewed

Ja

ÖFOS 2012

103021 Optik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/b722620e-8ab7-40d1-a9eb-b95e4925b71a