Optical switching property from a laser beam propagating in a Polymer Dispersed Liquid Crystals Film

Optical switching has been studied in epoxyÓbased polymer dispersed liquid crystal fìlms. A 'selfÓtransparency'effect is observed due to refractive index variations thermally induced either by heating the sample with a hot stage, or by absorption of the incident laser power. The swítching phenomena were studied for different liquid crystal contents in the composites, and experimental evidence of light modulation by a probe beam is also reported. The thermooptical behaviour of the material is correlated with the morphology of the samples. The results obtained verify the possibility of employing this type of material in optical devices based on the thermoÓoptical switching effect.