Subwavelength Fabry-Perot resonator: a pair of quantum dots incorporated with gold nanorod
1 Department of Mechanical Engineering, Chang Gung University, 259 Wen-Hwa 1st Rd, Kwei-Shan, Tao-Yuan, 333, Taiwan
2 Center for Biomedical Engineering, Chang Gung University, Tao-Yuan, 333, Taiwan
3 Institute of Applied Mechanics, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei, 106, Taiwan
Nanoscale Research Letters 2012, 7:546 doi:10.1186/1556-276X-7-546Published: 2 October 2012
The two apexes of an elongated gold nanorod (GNR) irradiated by a plane wave are shown to be the hotspots at the longitudinal plasmon modes. This phenomenon implies that a pair of quantum dots (QDs) located at these apexes might be excited simultaneously if the excitation band of QDs coincides with one of these modes. Consequently, a coherent emission of the two emitters could happen subsequently. In the following coherent emission, these two-level emitters are simulated as two oscillating dipoles (bi-dipole) with some possible phase differences. Our results show that the maximum radiative and nonradiative powers of the bi-dipole occur at the longitudinal plasmon dipole, quadrupole, sextupole, and octupole modes of GNR. Moreover, the strongest emissions are induced by the in-phase bi-dipole coupled to the odd modes and the 180° out-of-phase one to the even modes, respectively. The excitation and emission behaviors of a pair of QDs incorporated with GNR demonstrate the possibility of using this structure as a subwavelength resonator of Fabry-Perot type. In addition, the correlation between these modes of the GNR and the dispersion relation of gold nanowire is also discussed.