Investigating Molecular Spontaneous Emission Rate Enhancement Close to Elliptical Nanoparticles by Boundary Integral Method

Document Type : Articles

Authors

• Aida Firoozi
• Ahmad Mohammadi

Department of Physics, Bushehr Branch, Persian Golf University, Bushehr, Iran

Abstract

Utilizing boundary integral method (BIM), we investigate molecular
spontaneous emission rate enhancement in the vicinity of plasmonic nanoparticles of
elliptical cross section. These types of nanoparticles can considerably enhance the
molecule decay rate. The spontaneous emission rate can be modified by altering the
aspect ratio of the elliptical nanoparticle, the background refractive index and
nanoparticles material. It is shown that the decay rate can be enhanced by two or three
orders of magnitude for dipole distances below 10 nanometers. The position of
enhancement peaks can be adjusted in the investigated spectral range (400-1000 nm) by
changing the aspect ratio of the nanoparticle or the refractive index of background
medium and nanoparticles material. To validate our result, we use BIM method to
calculate light scattering by a circular gold nanowire and compare it with analytical
result. Then the effect of various parameters, including aspect ratio and material of
nanoparticle and the background refractive index, on the decay rate is investigated.

Keywords

• Spontaneous emission rate enhancement
• Plasmonic nanoparticles
• boundary integral method

20.1001.1.24237361.2016.1.3.3.4

---

References

.[1] E.M. Purcell, Spontaneous emission probabilities at radio frequency, Phys. Rev,
(1946) 69-681.
[2] A. Mohammadi, V.Sandoghdar, M. Agio, Gold nanorods and nanospheroids for
enhancing spontaneous emission, New Journal of Physics, (2008) 1-14.
[3] S.A. Maier, Plasmonics Fundamentals and Applications, Springer, New York,
(2007).
[4] L. Rogobete, F. Kaminski, M. Agio, V. Sandoghdar, Design of plasmonic
nanoantennae for enhancing spontaneous emission. Optics Letters, (2007) 1623-
1625.
34 * Journal of Optoelectronical Nanostructures Autumn 2016 / Vol. 1, No. 3
[5] A. Mohammadi, V. Sandoghdar, M. Agio, Gold, Copper, Silver and Aluminum
Nanoantennas to Enhance Spontaneous Emission, Journal of Computational and
Theoretical Nanoscience, (2009) 2024-2030.
[6] L. Novotny, and B. Hecht, Principles of Nano-Optics, Cambridge University Press,
Cambridge. England, (2006).
[7] Ch. Hafner, Post-modern Electromagnetics, John Wiley & Sons, Chichester, (1999).
[8] D. Sullivan, Electromagnetic Simulation Using the FDTD Method, IEEE Press,
(2000).
[9] A. Taflove, S.C. Hagness, Computational Electrodynamics: The Finite-difference
Time-domain Method, Artech House, Norwood, (2005).
[10] A.K, Aziz and I.M. BabuSka, Mathematical Foundations of the Finite Element
Method with Applications to Partial Differential Equations, Academic Press, New
York, (1972).
[11] L. Rogobete, C. Henkel, Spontaneous emission in a subwavelength environment
characterized by boundary integral equations, Physical Review A, (2004) 1-10.
[12] M.N. Vesperinas, Scattering and Diffraction in Physical Optics, John Wiley and
Sons, New York, (1991).
[13] C.mF.Bohren and D.R.Huffman, Absorption and Scattering by Small Particles.
Wiley, (1998) 194-208.