title: Deep-tissue light delivery via optrode arrays.
abstract: We establish performance characteristics of needle-type waveguides in three-dimensional array architectures as light delivery interfaces into deep tissue for applications, such as optogenetic and infrared (IR) neural stimulation. A single optrode waveguide achieves as high as 90% transmission efficiency, even at tissue depths >1  mm. Throughout the visible and near-IR spectrum, the effective light attenuation through the waveguide is ∼3 orders of magnitude smaller than attenuation in tissue/water, as confirmed by both simulation and experimental results. Light emission profiles from the optrode tips into tissue were also measured. Beam widths of 70 to 150 μm and full-angle divergence ranging from 13 to 40 deg in tissue can be achieved. These beam characteristics satisfy a wide range of requirements for targeted illumination in neural stimulation.
authors.affiliation: University of Utah, Department of Electrical and Computer Engineering, 36 Wasatch Dr., Salt Lake City, Utah 84112.
authors.forename: Tanya V F
authors.initials: TV
authors.lastname: Abaya
authors.affiliation: University of Utah, Department of Electrical and Computer Engineering, 36 Wasatch Dr., Salt Lake City, Utah 84112.
authors.forename: Mohit
authors.initials: M
authors.lastname: Diwekar
authors.affiliation: University of Utah, Department of Electrical and Computer Engineering, 36 Wasatch Dr., Salt Lake City, Utah 84112bUniversity of Utah, Department of Bioengineering, 50 S Central Campus Dr., Salt Lake City, Utah 84112.
authors.forename: Steve
authors.initials: S
authors.lastname: Blair
authors.affiliation: University of Utah, Department of Electrical and Computer Engineering, 36 Wasatch Dr., Salt Lake City, Utah 84112.
authors.forename: Prashant
authors.initials: P
authors.lastname: Tathireddy
authors.affiliation: University of Utah, Department of Electrical and Computer Engineering, 36 Wasatch Dr., Salt Lake City, Utah 84112.
authors.forename: Loren
authors.initials: L
authors.lastname: Rieth
authors.affiliation: University of Utah, Department of Electrical and Computer Engineering, 36 Wasatch Dr., Salt Lake City, Utah 84112bUniversity of Utah, Department of Bioengineering, 50 S Central Campus Dr., Salt Lake City, Utah 84112.
authors.forename: Florian
authors.initials: F
authors.lastname: Solzbacher
mesh_terms: D000042:Absorption; D000818:Animals; D001369:Axons / Q000473:pathology; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D003198:Computer Simulation; D004867:Equipment Design; D005898:Glass; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007259:Infrared Rays; D008027:Light; D051379:Mice; D018625:Microscopy, Atomic Force; D009474:Neurons / Q000473:pathology; D016011:Normal Distribution; D055095:Optics and Photonics / Q000379:methods; D011898:Ranidae; D012031:Refractometry; D012542:Scattering, Radiation; D012584:Sciatic Nerve / Q000473:pathology; D012685:Sepharose / Q000737:chemistry
chemical_list: D012685:Sepharose