Date and Time Wed, May 8th, 2013, 3:00 PM - 4:00 PM
Location Bahen Centre, Room 7180
Host Leon Yuan

Superoscillation-Based Optical Sub-Diffraction Microscopy

Alex M. H. Wong

Eleftheriades Group,EM



Optical microscopy suffers from a fundamental resolution limitation arising from the diffractive nature of light. Most current solutions to sub-diffraction optical microscopy involve combinations of near-field, non-linear and fine scanning operations, which hinder their use as a tool for general purpose microscopy. In contrast, we have recently proposed and demonstrated an optical super-microscope (OSM) – a linear imaging system with far-field working and observation distances. The OSM operates through a special phenomenon called superoscillation –where for a finite duration a waveform oscillates faster than its highest constituent frequency component. Harnessing superoscillatory optical waves, our OSM achieves far-field, sub-diffraction optical imaging without the need for fine scanning, data post-processing or object pre-treatment. Hence the OSM can be used in a wide variety of imaging applications beyond the diffraction limit, including real-time imaging of moving objects.

In this presentation I shall begin with a brief explanation on the diffraction limit and the shortcomings of present solutions to sub-diffraction imaging. Then I shall describe the phenomenon of superoscillation and explain how we have harnessed it to design the OSM. I shall thereafter report early characterization results, which demonstrate clear resolution improvement one can obtain with the OSM.


Alex Wong received a B.A.Sc. degree with honours from University of Toronto in Engineering Science (electrical option). During his undergraduate thesis research he worked under Prof. Li Qian on optical fiber-based pulse shaping algorithms. Following this he has earned his M.A.Sc. degree, and is currently in the PhD program in Electrical Engineering as a member of the Electromagnetics Group. His graduate research, supervised by Prof. George Eleftheriades, involves using electromagnetic waves to focus and image beyond the diffraction limit.