Implantable optrode design for optogenetic visual cortical prosthesis

The rise of optogenetic neural stimulation has opened new opportunities for neuroprosthesis such as visual cortical prosthesis, which necessitates an efficient delivery of light into the cortex. New forms of photosensitizing channelrhodopsin are reducing the required light intensities for stimulation, but implantable systems need to be highly efficient. Such efficiency calls for low loss in the transmission path, high coupling efficiency between the optic delivery system and optical emitter, as well as emitting efficiency from the light emitting diode. In this paper, we perform simulation results based on ray optics and illuminating theory as to the best strategy to attachment of optrode structures to Gallium Nitride-μLED arrays so as to maximize the efficiency of light delivery to the target neural tissue.Our results show that it is feasible to connect optrode elements and GaN-μLEDarrays for cortical stimulation and describe the optimisation requirements.