Share Email Print

Proceedings Paper

Bio-optical sensor for brain activity measurement based on whispering gallery modes
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

In this paper, a high-resolution bio-optical sensor is developed for brain activity measurement. The aim is to develop an optical sensor with enough sensitivity to detect small electric field perturbations caused by neuronal action potential. The sensing element is a polymeric dielectric micro-resonator fabricated in a spherical shape with a few hundred microns in diameter. They are made of optical quality polymers that are soft which make them mechanically compatible with tissue. The sensors are attached to or embedded in optical fibers which serve as input/output conduits for the sensors. Hundreds or even thousands of spheres can be attached to a single fiber to detect and transmit signals at different locations. The high quality factor for the optical resonator makes it significantly used in such bio-medical applications. The sensing phenomenon is based on whispering gallery modes (WGM) shifts of the optical sensor. To mimic the brain signals, the spherical resonator is immersed in a homogeneous electrical field that is created by applying potential difference across two metallic plates. One of the plates has a variable voltage while the volt on the other plate kept fixed. Any small perturbations of the potential difference (voltage) lead to change in the electric field intensity. In turn the sensor morphology will be affected due to the change in the electrostriction force acting on it causing change in its WGM. By tracking these WGM shift on the transmission spectrum, the induced potential difference (voltage change) could be measured. Results of a mathematical model simulation agree well with the preliminary experiments. Also, the results show that the brain activity could be measured using this principle.

Paper Details

Date Published: 30 May 2017
PDF: 8 pages
Proc. SPIE 10247, Bio-MEMS and Medical Microdevices III, 102470A (30 May 2017); doi: 10.1117/12.2265390
Show Author Affiliations
Amir R. Ali, The German Univ. in Cairo (Egypt)
Southern Methodist Univ. (United States)
Yasmin M. Massoud, The German Univ. in Cairo (Egypt)

Published in SPIE Proceedings Vol. 10247:
Bio-MEMS and Medical Microdevices III
Sander van den Driesche; Ioanna Giouroudi; Manuel Delgado-Restituto, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?