title: Multisite silicon neural probes with integrated silicon nitride waveguides and gratings for optogenetic applications.
abstract: Optimal optogenetic perturbation of brain circuit activity often requires light delivery in a precise spatial pattern that cannot be achieved with conventional optical fibers. We demonstrate an implantable silicon-based probe with a compact light delivery system, consisting of silicon nitride waveguides and grating couplers for out-of-plane light emission with high spatial resolution. 473 nm light is coupled into and guided in cm-long waveguide and emitted at the output grating coupler. Using the direct cut-back and out-scattering measurement techniques, the propagation optical loss of the waveguide is measured to be below 3 dB/cm. The grating couplers provide collimated light emission with sufficient irradiance for neural stimulation. Finally, a probe with multisite light delivery with three output grating emitters from a single laser input is demonstrated.
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Euijae
authors.initials: E
authors.lastname: Shim
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Neurobiology, University of California, Los Angeles, CA 90095, USA.
authors.forename: Sotiris
authors.initials: S
authors.lastname: Masmanidis
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Mo
authors.initials: M
authors.lastname: Li
mesh_terms: D062308:Optogenetics / Q000379:methods*; D010775:Photic Stimulation / Q000379:methods*; D019736:Prostheses and Implants; D017655:Silicon Compounds / Q000378:metabolism*
chemical_list: D017655:Silicon Compounds; C032734:silicon nitride