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 SUPER-RESOLUTION

IMAGING & THERAPY

The objective of this research is to develop viable super-resolution imaging technologies at the microwave (microstructured) and optical (nanostructured) regimes, as well as associated therapy applications.

 A great challenge towards the achievement of sub-diffraction imaging is the short "working distance" which is typically needed between the imaging apparatus and the object to be imaged. If the "working distance" issue could be relaxed, the rewards would be very significant. For example, microwaves can penetrate well in inorganic and organic materials (including the human body). However, the achieved resolution is poor for many applications due to the relatively long wavelength at microwaves (several centimetres). It should be pointed out that there is a trade-off between increasing the resolution by using shorter wavelengths (e.g. millimetre or terahertz frequencies) and penetration depth. Therefore, a viable technology that can retain the advantage of the long-range penetration depths of microwaves, while offering sub-wavelength resolution, can lead to a paradigm shift in imaging technology.

On the other hand, at infra-red and optical frequencies, relaxing the working distance between the sample to be imaged and the imaging apparatus can have multiple benefits including (a) imaging of buried objects (b) imaging of sensitive biological specimens (due to the non-invasive nature offered by a longer working distance) and (c) simplification of apparatus such as near-field optical microscopes.

Another very important challenge to overcome is the ability to achieve super-resolution imaging without the use of fluorescent labelling that can lead to damaging the tissue to be imaged.

To achieve these goals we are working on a combination of the following approaches (a) metamaterial-based imaging structures   (b) metascreens and (c) super-oscillations.

 

IMAGES

Optical Super-Microscope
Super-oscillation focusing beyond the diffraction limit
Sub-diffraction resolution of two apertures (bottom: conventional microscope, top: super-microscope)
Super-oscillations at microwaves
Sub-diffraction resolution with a metascreen
 


References

[1] A.M.H. Wong and G.V. Eleftheriades, ``An optical super-microscope for far-field real-time imaging beyond the diffraction limit", Sci. Rep., 3, 1715, issue 7, (2013).


[2] X. Han Dong, A.M.H. Wong, M. Kim and G.V. Eleftheriades, ``Superresolution far-field imaging of complex objects using reduced superoscillating ripples",  Optica, vol. 4, pp. 1126-1133, issue 9, Sept. 2017.


[3] L. Markley, A.M.H. Wong, Y. Wang and G.V. Eleftheriades, "Spatially shifted beam approach to sub-wavelength focusing", Physical Review Letters, 101, 113901, Sept. 12, 2008.


[4] A.M.H. Wong and G.V. Eleftheriades, ``Roadmap on superoscillations: An antenna array approach to superoscillations," Journal of Optics, Institute of Physics (IOP), vol. 21, no. 5, 18 April 2019.