A dual-shank neural probe integrated with double waveguides on each shank for optogenetic applications

This paper presents a dual-shank neural probe integrated with double-waveguides on each shank, which enables both optical stimulation and electrical recording. Two 15-μm-thick polymeric (SU-8) waveguides on each neural probe shank have been precisely defined by photolithography with a width of 24 μm and a spacing of 10 μm. The waveguides transmit a light coupled from optical fibers which are placed in the grooves located at the neural probe body. Each shank has 8 iridium recording electrodes which have the area of 11 μm × 13 μm. In front of each waveguide, four recording sites are deployed with a pitch of 100 μm. Blue light (473 nm in wavelength) has been successfully transmitted to the stimulation sites located at the end of the fabricated neural probe tips.