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KOÇ UNIVERSITY PHYSICS SEMINAR
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Speaker : Aykutlu Dana, UNAM-Bilkent University
Title : Nanophotonics for Mobile Chemical and Biological sensing
Date : December 26, 2017 Tuesday
Time : 2:30 P.M.
Cookie & Tea : SCI 103 2:15 P.M.
Place : SCI 103
web : https://physics-seminars.ku.
Abstract:
Nanophotonics has been extensively used for sensing applications over the last few decades, however practical issues hinder wide spread application of such sensors. In this talk, I am going to present several novel approaches for chemical and biomolecular sensing using plasmonics and nano/micro photonics, overcoming some of these practical problems. Large area plasmonic substrates that enable surface enhanced Raman spectroscopy on a mobile phone will be discussed. A photonic design that enables surface enhanced infrared absorption spectroscopy with an overall enhancement that surpasses optimal plasmonic designs will be presented. Using such substrates, infrared spectroscopy of nanometer thick biomolecular and inorganic layers is done on a mobile phone using low-cost miniature bolometer arrays, allowing identification of different chemicals. Surface plasmon resonance (SPR) sensors are very sensitive to the changes in the dielectric environment, thus are commonly employed to detect analytes adsorbed on the sensor surfaces. However, the response of the sensor to the bulk refractive index changes have to be accounted for to suppress response fluctuations in the temperature, pressure, and concentration of the analyte solution. Several strategies for self-referencing plasmonic sensing are discussed. Handheld and smartphone integrated plasmon resonance systems are demonstrated. For biosensing to be practical or clinically useful, picomolar concentrations of proteins must be detectable, while non-labeled conventional plasmonic sensors require optimal design to achieve such performance. Here, a novel plasmonic sensing scheme is presented that can detect femtomolar range concentration of proteins, DNA and small molecules, comparing favorably with the present literature. Overall, the demonstrations suggest that, enabled by nanophotonics, point-of-care chemical and biomolecular sensing is closer to the consumer market than ever.