Novel Electrically Controlled Periodic Optical Structures in the LC:PDMS Architecture ^†

Abstract

Optofluidics is a constantly developing research area that combines known technologies from chemistry and photonics. Various systems have been created, which are used in biology and chemistry as well as in other subjects. The combination of materials such as polydimethylsiloxane (PDMS) and liquid crystal (LC) provides a number of possibilities to create functional structures. The properties of LC allow systems to be developed in PDMS, e.g., lenses with different focal lengths depending on the polarization of light or multiplexers have been proposed. Appropriately controlling LC molecule orientation is a crucial element in creating tunable systems. The motivation of this research is to determine the proper arrangement of an electrode array to control the orientation of liquid crystal molecules and thus the refractive index. The performed tests allowed the initial parameters to be determined to produce LC:PDMS structures with a periodic orientation of LC molecules. As the channel sizes have to be micrometer-scale, a proper electrode arrangement has to be developed. The materials from which electrodes can be created are also limited due to PDMS properties as well as the size of the channels. The plan is to create a tunable LC:PDMS structure with LC molecules in a periodic reorientation, which would allow the system to function as a tunable Bragg grating. It would be the first achievement of this kind, and it would open up new possibilities for the combination of liquid crystal and PDMS in photonic systems.