Two constructions of microfluidic structures are described in this paper. A fibre optic microcell for spectrophometric measurements and a microcell for fluorescence experiments were designed and tested. The structures were made of polymer optical fibres which were incorporated into polymeric material i.e. poly(dimethylsiloxane). The structures were tested as detectors in absorbance measurement (solutions of bromothymol blue with diffierent pH were used) and in fluorescence tests (solution of fluoresceine was used).

In this work studies on propagation properties of a microstructured polymer optical fibre infiltrated with a nematic liquid crystal are presented. Specifically, the influence of an infiltration method on the LC molecular alignment inside fibre air-channels and, thus, on light guidance is discussed. Switching between propagation mechanisms, namely the transition from modified total internal reflection (mTIR) to the photonic bandgap effect obtained by varying external temperature is also demonstrated.