Data and Time April 10 , 2012, 3:00-4:15 PM
Location Sanford Fleming Building (SF), Room B560
Host Leon Yuan

Plasmonic Antennas and Arrays for Optical Imaging and Sensing

Yan Wang

The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Electromagnetics, Photonics)


Antennas have been a fundamental building block in modern telecommunication systems and electronic devices.  Their ability to effectively connect the free-space propagation and the transceiver circuitry has been their predominant application at RF and microwave frequencies.  Unlike microwave antennas that are inspired by wireless communications, optical antennas stem from high-resolution microscopy; their ability of converting far-field laser radiation to localized near-field energy (and vice versa) has enabled scanning near-field imaging with sub-diffraction resolution.  The current optical antenna research is driven by strong field enhancement and localization, which are characteristics of surface plasmons.  Although optical antennas are still in their infancy compared to their microwave counterparts, they prove to be useful for many optical applications, such as enhanced fluorescence and Raman spectroscopy, photovoltaic and LEDs, which extend beyond the conventional applications of microwave antennas.

This talk will give a brief overview of the early and current development of optical antennas, as well as a few examples of the optical applications that benefit from employing antenna structures.  Focus will be given to optical microscopy and spectroscopy.  Some major differences between the optical and conventional microwave antennas, such as the material (e.g. metals) properties, the excitation schemes, and the wavelength scaling issues will be discussed.  Finally, a proposed design based on the near-field "radiationless interference" utilizing optical antenna-array will be presented to demonstrate its potential in improving sub-diffraction imaging applications.  This work is inspired by a similar design at microwave frequency based on the "shifted-beam" near-field antenna-array, which significantly extends the working distance of the near-field probe.



Yan Wang is a senior PhD student in the Electromagnetics group under the co-supervision of Prof. Eleftheriades and Prof. Helmy.  She completed her BASc (+PEY) and MASc in 2004 and 2006 respectively, from the Electrical Engineering department at UofT.  From 2002-2003, she worked at MDRobotics for her PEY internship on the Canadarm2 project.  Her Master's project involved analyzing the properties of surface plasmons in planar waveguides, and designing ultra-compact integrated optical circuits utilizing plasmonics.  Her current research focuses on adapting microwave antenna designs for optical applications.  In her spare-time, she enjoys running, ultimate Frisbee and snowboarding.