Fano Resonance in an Electrically Driven Plasmonic Device

Abstract

We present an electrically driven plasmonic device consisting of a gold nanoparticle trapped in a gap between two electrodes. The tunneling current in the device generates plasmons, which decay radiatively. The emitted spectrum extends up to an energy that depends on the applied voltage. Characterization of the electrical conductance at low temperatures allows us to extract the voltage drop on each tunnel barrier and the corresponding emitted spectrum. In several devices we find a pronounced sharp asymmetrical dip in the spectrum, which we identify as a Fano resonance. Finite-difference time-domain (FDTD) calculations reveal that this resonance is due to interference between the nanoparticle and electrodes dipolar fields, and can be conveniently controlled by the structural parameters. Electrically driven plasmonic devices may offer unique opportunities as a research tool and for practical applications [1][2][3][4][5] . In such devices, current that flows across a metallic tunnel junction

Sub-nanometre control of the coherent interaction between a single molecule and a plasmonic nanocavity

“…Such coupling enables the quantum interference between two paths of emission through either the molecular transition or the plasmon resonance, leading to the Fano lineshape observed. We would like to note that electrically driven Fano resonance can also be observed for a gold nanoparticle in the gap between two electrodes17. In our work, the feature of the Fano lineshape can be modulated spatially by modifying the coupling strength between the molecule and nanocavity plasmon, and spectrally by the energy detuning between the molecular transition and plasmon resonance, Δ= ω p − ω m , as we will explain in detail below.…”

“…The plasmonic nanocavity is particularly attractive in this regard because of its capability to squeeze the optical fields down to the nanoscale, with much enhanced local density that promotes the coupling of the cavity with a single emitter, in spite of ohmic losses121314. When a quantum emitter is within a resonant plasmonic nanocavity, quantum interference may occur due to the coherent interaction between the discrete state of the emitter and the continuum-like state of the cavity, resulting in distinctive spectral features called Fano resonances15161718. This coherent interaction could also affect the energy level of the quantum emitter itself and result in a shift of optical transition energy, known as the photonic Lamb shift192021.…”

Quantum Coherent Multielectron Processes in an Atomic Scale Contact

“…On one hand, very high current densities may be achieved for electrons at energies beyond the Fermi level. On the other hand, such junctions support localized plasmon modes that drastically enhance electromagnetic fields [1][2][3][4][5][6][7]. A consequence of this coincidence is that light affects the conductance of the junction [8][9][10], another one is the emission of photons, which is driven by the shot noise of the current and corresponds to inelastic tunneling processes [11][12][13][14].…”

Exciton-Polariton Fano Resonance Driven by Second Harmonic Generation

“…A Fano resonance originates from the interference between a discrete state and a continuum of quantum states, giving rise to a characteristic asymmetric emission line shape. First introduced to describe the atomic photo-ionization [1,2], exploration of this important phenomenon and the underlying physics have been extended to the field of photonic crystals [3][4][5], plasmonic devices [6,7], metamaterials [8][9][10], fibercavity system [11], Raman scattering [12], nonlinear optical regime [14,15], etc. [16][17][18][19][20][21].…”