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Proceedings Paper

Thermo-optical effects and fiber optic sensing device based on polymer dispersed liquid crystals
Author(s): Luigi Sirleto; Giancarlo C. Righini; Leonardo Ciaccheri; Mahmoud Abu Rish; Francesco F. Simoni
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Paper Abstract

In this paper an experimental study of thermo-optical properties of polymer dispersed liquid crystals (PDLC), prepared by PIPS in bulk and in confined cylindrical geometry, is presented. The transmissivity of PDLC In bulk as a function of temperature proves the existence of temperature optical switching. We have also demonstrated the existence of optical bistability, which could be interesting in develop of logical optical devices as optical memory elements. A bistable al fiber optic sensors based on PDLC is also presented. In this device PDLC permits at the same time the optomechanical interconnection of tow fibers and the modulation of the light crossing the device. As the modulation can be controlled by external temperature, the device has been proved to be suitable for the realization of a heat flow sensor. Without any optimization of the device we have obtained an ON-OFF contrast of 8 dB and a response time comparable with other conventional device using nematic LCs. This sensor is compact, rugged and is cheap, because it does not require a complex fabrication and alignment technology. It presents the typical advantages of both the fiber optic sensor and the liquid crystal technology. We note that its main advantage is a small thermal capacity, which is comparable with electronic device as thermistors, and it represents a significant improvement for the sensor based on liquid crystals. Further theoretical studies are necessary in order to understand in depth it thermo-optical characteristics.

Paper Details

Date Published: 15 May 2001
PDF: 8 pages
Proc. SPIE 4277, Integrated Optics Devices V, (15 May 2001); doi: 10.1117/12.426823
Show Author Affiliations
Luigi Sirleto, Univ. degli Studi di Napoli Federico II (Italy)
Giancarlo C. Righini, Istituto di Ricerca sulle Onde Elettromagniche (Italy)
Leonardo Ciaccheri, Istituto di Ricerca sulle Onde Elettromagniche (Italy)
Mahmoud Abu Rish, Bethlehem Univ. (Israel)
Francesco F. Simoni, INFM and Univ. di Ancona (Italy)

Published in SPIE Proceedings Vol. 4277:
Integrated Optics Devices V
Giancarlo C. Righini; Seppo Honkanen, Editor(s)

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