Evening Lecture:

Negative Refractive Index Materials

Abstract:
While all naturally occurring materials have a positive refractive index, by synthesizing a suitable metamaterial and operating it beyond the electric and magnetic dipole resonance, it's possible to achieve a negative refractive index, with concomitant negative refraction. Perhaps the most interesting consequence of a negative index is the possibility of evanescent field growth and circumventing the wavelength limit for image resolution. The potential technological impact is as diverse as memory density, lithography, and microscopy. A passive causal resonant system, as dictated by the Kramers-Kronig relations, should have some degree of loss, and I present the consequence of perturbational loss on the possible resolution. Interestingly, with such imperfect lenses, we find vortices, which themselves may be useful. A relatively simple way to achieve subwavelength resolution, using the appropriate polarization, is with a multilayer metal-insulator system, and I present some preliminary results. While these metamaterials are periodic, they don't need to be, and I generalize with the concept of irregular field transformation structures, which offer some remarkable features for optical signal processing, and for sources and detectors. Finally, I show how fields between metal surfaces can be resonantly enhanced, thereby providing a new mechanism for surface enhanced Raman scattering and also for nanoparticle waveguides. These structures should be important in spectroscopy and integrated optics.

Presenter(s):
Dr Kevin Webb is a Professor of Electrical and Computer Engineering at Purdue University, Indiana. More information on his research areas may be found on his website at http://cobweb.ecn.purdue.edu/~webb/index.html

Registration is encouraged though visitors are welcome. For further information, please contact Dr. Kamran Ghorbani (kamran.ghorbani@rmit.edu.au).

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