Mark S. Wheeler

Ph.D. Candidate
The Edward S. Rogers Sr. Department of Electrical and Computer Engineering
University of Toronto
10 King's College Road
Toronto, Ontario, M5S 3G4, Canada

E-mail: mark {dot} wheeler (and append {at} utoronto {dot} ca)
Office: Bahen 4167
Phone: 416-978-6389

A Scattering-Based Approach to the Design, Analysis, and Experimental Verification of Magnetic Metamaterials Made from Dielectrics

Metamaterials are composite materials with engineered electromagnetic properties which are often rare or absent in nature. Several exciting phenomena are made possible with the realization of metamaterials, including sub-wavelength imaging, reversal of Snell's Law, and invisibility cloaking. Although some evidence of these phenomena has been published, much effort is still required to design and fabricate satisfactory metamaterial structures, particularly in the optical regime.

The main focus of our research has been on developing, modeling, fabricating, and characterizing metamaterial structures. In particular, composites made from mixtures of non-magnetic spherical particles are used to create magnetic properties at optical frequencies. With careful design the composites may have exotic properties such as negative permeability and negative index of refraction. Most notably, we have modeled and experimentally verified a magnetic response at infrared frequencies in a simple sample: a milled micropowder of silicon carbide, where the particles are polydisperse and the shapes are totally random. The minimal processing required by such an unrefined sample stands in stark contrast to other metamaterials designs, which require laborious methods and costly facilities.

More recently, we have applied multiple scattering theory to small clusters of dielectric particles. Hybridized modes arise, with various magnetic or electric dipole (or other multipolar) modes which depend on the particular configuration. These may be considered as meta-molecules for inclusion in metamaterials, allowing for extra degrees of freedom in the engineering of material properties.

Ph.D. Candidate, Electrical and Computer Engineering (Photonics/Electromagnetics), March 2010 (Expected)
Department of Electrical and Computer Engineering
University of Toronto, Ontario, Canada
Advisors: Prof. Mohammad Mojahedi and Prof. J. Stewart Aitchison

Bachelor of Applied Science, Electrical and Computer Engineering (Co-op), 2002
Department of Electrical and Computer Engineering
University of Windsor, Ontario, Canada

Institute of Electrical and Electronics Engineers (IEEE) (Student Member)
American Physical Society (APS) (Student Member)
Optical Society of America (OSA) (Student Member)

1. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Coupled magnetic dipole resonances in sub-wavelength dielectric particle clusters," submitted, J. Opt. Soc. Am. B (2009)
2. T. Xu, M. S. Wheeler, H. E. Ruda, M. Mojahedi, and J. S. Aitchison, "The influence of material absorption on the quality factor of photonic crystal cavities," Opt. Express, vol. 17, pp. 8343-8348 (2009). [abstract]
3. M. S. Wheeler, J. S. Aitchison, J. I. L. Chen, G. A. Ozin, and M. Mojahedi, "Infrared magnetic response in random silicon carbide micropowder," Phys. Rev. B, vol. 79, 073103 (2009). [abstract]
4. T. Xu, M. S. Wheeler, S. V. Nair, H. E. Ruda, M. Mojahedi, and J. S. Aitchison, "Highly confined mode above the light line in a photonic crystal slab," Appl. Phys. Lett., vol. 93, 241105 (2008). [abstract]
5. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Coated non-magnetic spheres with a negative index of refraction at infrared frequencies," Phys. Rev. B, vol. 73, 045105 (2006). [abstract]
6. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Three-dimensional array of dielectric spheres with an isotropic negative permeability at infrared frequencies," Phys. Rev. B, vol. 72, 193103 (2005). [abstract]
7. J. F. Woodley, M. S. Wheeler, and M. Mojahedi, "Left-handed and right-handed metamaterials composed of split ring resonators and strip wires," Phys. Rev. E, vol. 71, 066605 (2005). [abstract]
8. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Negative refraction in a photonic crystal with a metallic cross lattice basis," Phys. Rev. B, vol. 71, 155106 (2005). [abstract]

1. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Magnetic dipoles induced in dielectric spheres: Coupled interactions," Conference on Lasers and Electro-Optics (CLEO)/International Quantum Electronics Conference (IQEC) Technical Digest, Baltimore, Maryland, paper IThL5 (2009). [abstract]
2. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Magnetic response in non-magnetic materials and coupled dipole interactions," IEEE Antennas and Propagation Society (AP-S) International Symposium, San Diego, California (2008). [abstract]
3. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Experimental confirmation of infrared magnetic response in a random silicon carbide micro-powder," Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science (QELS) Technical Digest, San Jose, California, paper QPDB4 (2008). [abstract]
4. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Negative permittivity and permeability in the infrared due to dielectric spheres," Proceedings of SPIE, Photonics North, Toronto, Ontario, Canada, vol. 5971, 597113 (2005). [abstract]
5. J. F. Woodley, M. S. Wheeler, and M. Mojahedi, "Determining the sign of the index in metamaterials composed of split ring resonators and strip wires using dispersion diagrams or the insertion phase," Proceedings of SPIE, Photonics North, Toronto, Ontario, Canada, vol. 5971, 59711O (2005). [abstract]
6. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "Magnetism and effective electromagnetic parameters from dielectric spheres," Proceedings of IASTED Conf. on Antennas, Radar, and Wave Propagation, Banff, Canada, paper 475-143 (2005).
7. J. F. Woodley, M. S. Wheeler, and M. Mojahedi, "Left-handed and right-handed metamaterials composed of split ring resonators and strip wires," IEEE Antennas and Propagation Society (AP-S) International Symposium, Washington D.C., vol. 3A, pp. 786-789 (2005). [abstract]
8. M. S. Wheeler, J. S. Aitchison, C. D. Sarris and M. Mojahedi, "Tunable metallic photonic crystals with an effective negative index of refraction," IEEE Antennas and Propagation Society (AP-S) International Symposium, Monterey, California, vol. 2, pp. 1407-1410 (2004). [abstract]
9. M. S. Wheeler, J. S. Aitchison, and M. Mojahedi, "A novel two-dimensional negative index metamaterial suitable for planar processing", Bulletin of the American Physical Society, Montréal, Quebec, Canada, vol. 2, no. 1, part II, p. 1069 (2004).