Neural probes integrated with optical mixer/splitter waveguides and multiple stimulation sites

This paper reports new neural probe schemes incorporating various optical waveguides for optogenetic applications. A photodefinable polymer (SU-8) has been patterned to form optical mixer and splitter waveguides for advanced optical functions with multiple light sources and easy delivery of light to multiple shanks, respectively. Also, multiple stimulation sites have been implemented by step-wise patterning in a single waveguide. In addition to SU-8 waveguides, iridium electrodes have been integrated for recording of neural signals from optically stimulated neurons with light of specific wavelengths. Single mode optical fibers have been coupled in grooves etched in the probe body. We have successfully demonstrated transmissions of blue light, 473 nm in wavelength, through the waveguides that are integrated on the fabricated devices.