Fig. 1: Fabrication of implantable EO-Flex probes along with optical and electrical characterization.
a Silica microfibers of defined length are positioned on a silicon substrate to allow a single-mode fiber (SMF)-loaded ferrule to bond to the microfiber. b (from top to bottom) Photographs show the active alignment and bonding process of coupling the microfiber to the SMF. c Schematic of the electrodeposition setup for depositing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) after the sputtering of iridium oxide (IrOx). d Optical image of the light output of a probe from the side as the light reflects from a mirror, and from the cleaved end-facet (zoom-in insets) with and without laser light. (inset) Fluorescence image capturing the cone angle of the probe after submerging it in a dye solution and launching blue (442 nm) light into the probe. Micrographs were generated over a couple of experiments. e Cross-sectional electron micrograph of an EO-Flex probe after milling the end showing the exposed conductive rings along with the optical glass (SiOx) core. Multiple electron micrographs were recorded for similar probes resulting in similar properties. f EIS data for milled probes with (black line) and without (green line) the PEDOT:PSS cladding. Average impedance is shown with the lightly shaded area representing one standard deviation for n = 4 probes. g A cross-sectional view of the probe showing its various cladding layers. h Photograph of a completed EO-Flex probe with a zoom-in of the microfiber tip region. For scaling strategies, see Fig. S16.
