Physics Seminar: "Tapered Optical Fibers for Biosensing Applications"

Wright State University Physics Department Seminar
Friday, October 24, 2014 at 3:00pm in 204 Fawcett

"Tapered Optical Fibers for Biosensing Applications"
By Karolyn M. Hansen, Department of Biology; Peter E. Powers, Department of Physics; Joseph Haus, Electro-Optics Graduate Program at the University of Dayton, Dayton OH

ABSTRACT
This study focuses on the design, fabrication, and characterization of tapered optical fibers for label-free, biomolecular sensing in both aqueous and gaseous environments. Single mode fibers were tapered to a diameter of approximately 10 microns allowing for the propagation of multiple modes that create an interference pattern in the output signal. The physical dimensions of the tapered fibers were measured for use in multimodal output simulations, which were then compared to the empirically determined output signal. Tapered regions serve as the sensing interface, such that the light propagating through/around the fiber interacts with molecules tethered to the tapered surface. Tapered regions are functionalized with biomolecules for capture/detection of analytes in both aqueous and vapor phases. Molecular binding of analytes with recognition molecules changes the refractive index and the thickness of the biolayer, which can be measured as a phase shift in the output. The sensing platform (fiber and PDMS flowcell) was designed such that the device could be fabricated and constructed quickly and economically. We envision the use of tapered optical fibers in array format for detection of multiple analytes in complex samples for biomedical (blood, saliva, breath), environmental, and homeland security applications.