Hatef Ali, Sadeghi Seyed M, Fortin-Deschênes Simon, Boulais Etienne, Meunier Michel
École Polytechnique de Montréal, Laser Processing and Plasmonics Laboratory, Engineering Physics Department, Montréal, Québec H3C 3A7, Canada.
Opt Express. 2013 Mar 11;21(5):5643-53. doi: 10.1364/OE.21.005643.
It is well-known that optical properties of semiconductor quantum dots can be controlled using optical cavities or near fields of localized surface plasmon resonances (LSPRs) of metallic nanoparticles. In this paper we study the optics, energy transfer pathways, and exciton states of quantum dots when they are influenced by the near fields associated with plasmonic meta-resonances. Such resonances are formed via coherent coupling of excitons and LSPRs when the quantum dots are close to metallic nanorods and driven by a laser beam. Our results suggest an unprecedented sensitivity to the refractive index of the environment, causing significant spectral changes in the Förster resonance energy transfer from the quantum dots to the nanorods and in exciton transition energies. We demonstrate that when a quantum dot-metallic nanorod system is close to its plasmonic meta-resonance, we can adjust the refractive index to: (i) control the frequency range where the energy transfer from the quantum dot to the metallic nanorod is inhibited, (ii) manipulate the exciton transition energy shift of the quantum dot, and (iii) disengage the quantum dot from the metallic nanoparticle and laser field. Our results show that near meta-resonances the spectral forms of energy transfer and exciton energy shifts are strongly correlated to each other.
众所周知,半导体量子点的光学性质可以通过光学腔或金属纳米颗粒的局域表面等离子体共振(LSPR)近场来控制。在本文中,我们研究了量子点在受到与等离子体元共振相关的近场影响时的光学、能量转移途径和激子态。当量子点靠近金属纳米棒并由激光束驱动时,这种共振通过激子和LSPR的相干耦合形成。我们的结果表明,对环境折射率具有前所未有的敏感性,导致从量子点到纳米棒的Förster共振能量转移以及激子跃迁能量发生显著的光谱变化。我们证明,当量子点 - 金属纳米棒系统接近其等离子体元共振时,我们可以调节折射率以:(i)控制从量子点到金属纳米棒的能量转移被抑制的频率范围,(ii)操纵量子点的激子跃迁能量位移,以及(iii)使量子点与金属纳米颗粒和激光场脱离。我们的结果表明,在接近元共振时,能量转移的光谱形式和激子能量位移彼此强烈相关。