Fiber electric double-layer platform for a phase shifter based on the Pockels effect of liquid molecules

The electric double layer (EDL) was formed at the interface of the electrode and liquid and has been widely used in a series of applications, ranging from batteries to biosensors, based on the electrical property changes. In this paper, we demonstrate a simple microfiber phase shifter based on the Pockels effect of liquid in the electric double layer. By constructing an EDL around the microfiber, the phase shifter can be achieved. Furthermore, the effects of ion concentration and molecular polarity of liquids on this phase shifter were studied. The fiber electric double-layer platform has the advantages of low voltage modulation and simple fabrication, which has the potential for use in wearable sensing devices, biopotential detection, and biomolecule detection.