Implantable glass optrodes for deep-tissue light delivery

3D needle-type glass waveguide arrays were developed as potentially compact neural interfaces for light delivery in deep-tissue. As much as 90% of input light is transmitted via a single optrode to depths >1mm in tissue. Light emission profiles from the optrode tips into tissue can exhibit beam widths of 70-150 μm and full-angle divergence ranging from 13-40°. These beam characteristics may be able to satisfy a wide range of requirements for targeted illumination in neural stimulation.