Research: Electromagnetics of photonic nanostructures

· Nano-sized metal-dielectric composite elements have a number of interesting properties that can lead to important applications. Many metals in the optical (e.g. near-IR and visible) regimes operate as plasmas characterized by a negative real part of the permittivity. Due to this property nano-sized metal particles can support resonances at wavelength much greater than their size, which can be used in various novel applications. One of our projects is to design and fabricate a laser of size smaller than the wavelength in all three dimensions. An important component of this study is to reduce the inherent radiation and dissipation losses in subwavelength resonators [3].

· Nano-scale elements coupled with metal-dielectric surfaces can support an even richer variety of optical phenomena, many of which are only possible due to the interaction between the arrays and surfaces (see an example in Fig. 2). We are studying wave phenomena supported by isolated and arrays nano-particles associated with interaction between various field types, including resonant fields supported by isolated nanoparticles, traveling waves supported by linear nanoparticle arrays, surface waves/surface plasmon polaritons supported by metal-dielectric surfaces, as well as various leaky waves appearing due to these interactions (e.g. [4-12]).

· Twisted arrays of nanoparticles.

Time evolution of the electric field supported by a straight chain of gold nano-bumps of size (100nmx100nm) residing directly on a gold surface ([6]). The field is shown in the horizontal plane at 50 nm from the top edge of the nano-bumps. The structure is excited by a dipole source relatively far from the chain. This source excited a surface plasmon polariton on the gold surface, which is scattered from the chain.

Photonic nanostructures (back)

Time evolution of the electric field supported by a chain of gold nano-bumps of size (100nmx100nm) residing directly on a gold surface and having a 90 degree bend ([6]). The field is shown in the horizontal plane at 50 nm from the top edge of the nano-bumps. The structure is excited by a dipole placed near the left bottom end of the chain. This source excites a surface plasmon polariton on the gold surface as well as a traveling wave along the chain. The surface plasmon polariton is scattered from the chain. The traveling wave propagates without radiation loss along the chain and it also propagates through the sharp edge.

References

1. V. Lomakin, Y. Fainman, Y. Urzhumov, and G. Shvets, "Doubly negative metamaterials in the near infrared and visible regimes based on thin films," Optics Express, vol. 14, n. 23, pp. 11164-11177, 2006.

2. V. Lomakin, Y. Fainman, Y. Urzhumov, and G. Shvets, "Optical metamaterials based on thin metal films: From negative index of refraction to enhanced transmission," SPIE, San Diego, California, August 2007 (invited).

3. A. Mizrahi, V. Lomakin, B.A. Slutsky, M.P. Nezhad, L. Feng, and Y. Fainman, "Low threshold gain metal coated laser nanoresonators," Optics Letters, vol. 33, no. 11, pp. 1261-1263, 2008.

4. L. Feng, K.A. Tetz, B. Slutsky, V. Lomakin, and Y. Fainman, "Fourier plasmonics: Diffractive focusing of in-plane surface plasmon polariton waves", Applied Physics Letters, vol. 91, 081101, 2007.

5. D. Van Orden, Y. Fainman, and V. Lomakin, "Optical waves on nano-particle chains coupled with metal-dielectric surfaces," Conference on Lasers and Electro-Optics (CLEO/QELS), San Jose, California, May 2008.

6. V. Lomakin, M. Lu, and E. Michielssen, "Optical wave properties of nano-particle chains coupled with a metal surface," Optics Express, vol. 15, pp. 11827-11842, 2007.

7. V. Lomakin, S.Q. Li, and E. Michielssen, "Manipulation of stop-band gaps of periodically perforated conducting plates," IEEE Microwave and Wireless Components Letters, vol. 15, no. 12, pp. 919-921, 2005.

8. V. Lomakin and E. Michielssen, "Enhanced transmission through metallic plates perforated by arrays of subwavelength holes and sandwiched in between dielectric slabs," Physical Review B, vol. 71, no. 23, pp. 235117 - 1-10, 2005.

9. V. Lomakin, S. Li, and E. Michielssen, "Plane wave transmission through metal plates perforated by periodic arrays of through-holes of subwavelength coaxial cross-section," Microwave and Optical Technology Letters, vol. 49, no. 7, pp. 1554-1558, 2007.

10. V. Lomakin and E. Michielssen, "Beam transmission through periodic sub-wavelength hole structures," IEEE Transactions on Antennas and Propagation, vol. 55, no. 6, pp. 1564-1581, 2007.

11. V. Lomakin and E. Michielssen, "Transmission of transient plane waves through perfect electrically conducting plates perforated by periodic arrays of subwavelength holes," IEEE Transactions on Antennas and Propagation, vol. 54, no. 3, pp. 970-984, 2006.

12. V. Lomakin, N.W. Chen, S. Q. Li, and E. Michielssen, "Enhanced transmission through two-period arrays of sub-wavelength holes," IEEE Microwave and Wireless Components Letters, vol. 14, no. 7, pp. 355-357, 2004.

Computational Electromagnetics

Department of Electrical and Computer Engineering, University of California, San Diego