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. Author manuscript; available in PMC: 2014 Oct 1.
Published in final edited form as: J Neurosci Methods. 2013 Jul 15;219(1):142–154. doi: 10.1016/j.jneumeth.2013.06.011

Figure 1. The structure of the coaxial optrode.

Figure 1

(a) Cross sectional schematic (top) and side view photograph (bottom) of the coaxial optrode showing main constituent parts. The center optical fiber has a 10 μm diameter optical aperture (exposed core of the fiber) leading to highly directional light output as visualized in dye-doped saline. The saline contains ~1 μM fluorescein with fluorescence excited by 473 nm laser light (bottom). (b) A larger scale image of the device where the reinforcing thin stainless steel jacket (310 μm outer diameter) was kept few centimeters away from the tip leading to a thinner tissue penetrating portion of the shaft (diameter 165 μm). (c) Scanning electron microscope images of the coaxial optrode tip. The tip was polished to a flat circular tip of diameter 20-30 μm to separate the optical aperture from the surrounding gold recording electrode layer. This design reduced light-induced artifacts in the electrophysiological recordings to noise level. (d) Full length photograph of the coaxial optrode showing its electrical and optical connections at the distal end.