1. Greg Wigger, Chris Tedder, and Melanie Gault Advised by: Dr. Duco Jansen, Ph.D.

2.  This requires a reliable stimulation modality to gain better control over neural signals. There is a need for an implantable device that will reliably stimulate individual nerve fascicles

3. Infrared Stimulation Same advantages as electrical stimulation, but:  Less damaging to nerve  Artifact free  Spatially selective Electrical Stimulation Has fundamental shortcomings that create a need for an alternative  Contact can cause permanent damage to nerve  Stimulation artifact  Hard to selectively stimulate Rat Sciatic Nerve Electrical Stimulator -5 0 5 10 02468 121416 CMAP (V) Rat Sciatic Nerve Electrical Stimulator -5 0 5 10 02468 121416 CMAP (V)

4. Develop an infrared nerve stimulator containing optical fibers running parallel to the nerve fibers  Create a single fiber prototype that sends infrared signal at 90 ° angle  Three models will be tested Fiber with flat angled mirror Fiber polished at 45 degree angle Fiber with concave angled mirror

5.  Biocompatibility – PEGylation  Minimal Power Loss  Small Beam Size  Energy Density  Low Cost  Durability Flat Mirror PrototypeCurved Mirror Prototype

6.  Implantable devices for use in victims of paralysis  Incorporation of sensors to provide brain with feedback from the external environment

7.  Completed Solidworks  Tested nylon tube for infrared break down  Determined beam size, energy density, and power loss of 45 °- polished fiber and curved mirror prototype with “Knife- Edge Technique” Before After

9.  Energy Density and Beam Area  10-fold difference in energy density and order of magnitude difference in spot area of the beam

10.  Power Loss  Coupling loss measured from the laser to the fiber ▪ Faulty lens?  Nylon is either scattering or absorbing infrared light as seen in large loss from fiber to nylon ▪ Future direction

11.  Determine if nylon scatters or absorbs light by flattening a piece of nylon and measure loss and spot size  Find absorption spectra of nylon  Calculations  Find theoretical spot size of concave mirror and compare it to actual measured spot size  Find maximum distance that the fiber can be from the concave mirror without any light being lost

12.  Obtain capillary tube (600 µm ID)to determine if glass is more transparent to infrared light than the nylon tubing  We will conduct an energy-loss test using the angle-polished fiber  Determine the actual distance at which the curved mirror focuses  Place 100 µm pinholes over power meter

13.  Still waiting on our flat mirrors to arrive…  Optimistic about about its feasibility and effectiveness:  Unnecessary to polish the fiber, as with angle- polished model  Convergence/divergence are non-issues, as with concave model