Voltage Field Generated by a Single Photodiode in a Volume Conductor: Simulation and Measurements

Kimberlyn M. Gray, Hari K. Innamuri, Abdelkader Tayebi, Mesut Sahin

Research output: Contribution to journalConference articlepeer-review

5 Scopus citations

Abstract

One of the major challenges of neural stimulation is the mechanical stress and resulting neural trauma induced by the movement of the electrode interconnects. A potential way of eliminating interconnects is to use micro-stimulators that can be activated through optical means. To test this method, the voltage field generated by a single photodiode in a volume conductor was analyzed using finite element (FE) analysis. The voltage field was also experimentally tested using diodes with uncoated gold and electrodeposited iridium oxide film (EIROF) coated contacts pulsed with a near-infrared laser (NIR) beam. The EIROF coated microphotodiodes proved to have much larger current injection capabilities. Comparison of experimental results with the finite element model shows that the photodiode voltage is saturating at a few microamperes due to the high impedance of the contacts. However, the voltage generated is larger than 50 mV in peak at the cathodic contact. The voltage waveforms recorded directly from the contacts show that the interface needs a long time interval to discharge. This places a limit on the maximum frequency of stimulation.

Original languageEnglish (US)
Pages (from-to)2189-2192
Number of pages4
JournalAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
Volume3
StatePublished - 2003
Externally publishedYes
EventA New Beginning for Human Health: Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society - Cancun, Mexico
Duration: Sep 17 2003Sep 21 2003

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

Keywords

  • Electrodeposition
  • Neural interfaces
  • Neural stimulation
  • Photodiodes
  • Volume conductor models

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