Ibrahim Abdulhalim
Ben-Gurion University of the Negev, Israel
Title: Plasmonic biosensors on demand: Tunable penetration depth, compactness, ultrahigh sensitivity and enhanced spectroscopies
Biography
Biography: Ibrahim Abdulhalim
Abstract
Evanescent wave optical biosensors allow specifi c sensing by using a surface binding layer which enhances the capture
of specifi c bio-entities within the nanoscale neighborhood to the sensor surface. However, this evanescence region is
sometimes too small at the scale of few tens of nanometers which prevents obtaining monotonic signal versus concentration
when the bio-entities are larger than the optical penetration depth. Th e purpose of this study is to describe methods for
sensing both small (molecules, viruses, etc.) and large bioentities (cells, large molecules) using plasmonic sensors with
tunable penetration depth. During the last few years, we have been developing diff erent structural and system confi gurations
for improving the performance of plasmonic biosensors based on improving the reading method and enhancing the local
electromagnetic (EM) fi eld further for the purpose of improving the sensitivity and lowering the detection limit based on
SPR, SERS and SEF. Th e structural improvements include: (i) planar thin metal fi lms combined with dielectric fi lms, (ii)
periodic metallic structures on planar substrate, (iii) nanosculptured thin fi lms prepared by the glancing angle deposition
technique. (iv) long range self-referenced plasmonic confi gurations, and lately, (v) combination of nanostructures with thin
metal fi lms for coupling of extended surface plasmons (ESP) to localized surface plasmons (LSP). Th e system improvements
include: (i) diverging beam approach in the angular mode, (ii) polarimetric spectral mode, (iii) image and signal processing.
Particularly, we have shown recently that even much higher enhancement of the EM fi elds is obtained by exciting the LSPs
through extended surface plasmons generated on a semi-infi nite metallic fi lm surface. Biotechnology applications will be
presented for sensing biomolecules and cells in water and in blood. In spite of the technological advances in optics, the need
for developing molecular binding layer to improve the specifi city is still in demand from the biotechnology community.