An Electrically Excited Nanoscale Light Source with Active Angular Control of the Emitted Light

作者：Le Moal Eric^*; Marguet Sylvie; Rogez Benoit; Mukherjee Samik; Dos Santos Philippe; Boer Duchemin Elizabeth; Comtet Genevieve; Dujardin Gerald

来源：Nano Letters, 2013, 13(9): 4198-4205.

DOI：10.1021/nl401874m

• Scanning tunneling microscopy
• localized surface plasmon
• inelastic electron tunneling
• gold nanotriangle
• truncated tetrahedron
• photon nanosource

We report on the angular distribution, polarization, and spectrum of the emitted from light arises from the local, low-energy, electrical excitation of localized surface plasmons (LSP) on individual gold nanoparticles using a scanning tunneling microscope (STM). The gold nanoparticles (NP) are chemically synthesized truncated bitetrahedrons. The emitted light is collected through the transparent substrate and the emission characteristics (angular distribution, polarization, and spectrum) are analyzed. These three observables are found to strongly depend on the lateral position of the STM tip with respect to the triangular upper face of the gold NP. In particular, the resulting light emission changes orientation when the electrical excitation via the STM tip is moved from the base to the vertex of the triangular face. On the basis of the comparison of the experimental observations with an analytical dipole model and finite-difference time-domain (FDTD) calculations, we show that this behavior is linked to the selective excitation of the out-of-plane and in-plane dipolar LSP modes of the NP. This selective excitation is achieved through the lateral position of the tip with respect to the symmetry center of the NP.

• 出版日期2013-9