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
Applications
Yan Wang
The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Electromagnetics, Photonics)
Abstract:
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.
Biography:
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. |
|