The application of Liquid Crystals to integrated optics is actively investigated because the mechanical and optical properties of these materials can be exploited to realize new schemes of opto-electronic devices. In particular the molecular alignment induced in nematic liquid crystals by external electric fields can be very useful for mode splitting, tunable filtering and optical switching. The aim of this work is to experimentally demonstrate the possibility of dynamically reshaping the refractive index profile of a planar waveguide, and hence the propagation characteristics of the modes, by applying a small external electric field. Graded index planar waveguides have been realized by using a nematic liquid crystal in a distorted hybrid configuration as the guiding layer. The application of external electric fields enables to modify the orientation of the local molecular axis and hence to reshape in an easy and controlled way the refractive index profile. Extensive m-lines spectroscopy measurements were performed in order to determine the anisotropic refractive index profiles for various electric field strengths. The experimental results are in good agreement with what expected from a simple model based on the dielectric, optical and elastic properties of the liquid crystal guiding layer.
Dynamic control of the optical properties of a liquid crystal waveguide by means of an applied electric field / M. Marangoni, M. Buscaglia, R. Osellame, F. Mantegazza, T. Bellini, R. Ramponi (PROCEEDINGS OF SPIE, THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING). - In: Physics and Simulation of Optoelectronic Devices XI / [a cura di] M. Osinski, H. Amano, P. Blood. - [s.l] : SPIE, 2003. - ISBN 0819447862. - pp. 386-392 (( convegno Integrated optoelectronics devices tenutosi a San Jose nel 2003.
|Titolo:||Dynamic control of the optical properties of a liquid crystal waveguide by means of an applied electric field|
|Parole Chiave:||liquid crystals; hybrid nematic waveguide; liquid crystal waveguides; integrated optics|
|Settore Scientifico Disciplinare:||Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)|
|Data di pubblicazione:||2003|
|Enti collegati al convegno:||SPIE - The International Society for Optical Engineering|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1117/12.474399|
|Tipologia:||Book Part (author)|
|Appare nelle tipologie:||03 - Contributo in volume|