150 research outputs found
Near-Field Second-Harmonic Generation Induced by Local Field Enhancement
The field near a sharp metal tip can be strongly enhanced if irradiated with an optical field polarized along the tip axis. We demonstrate that the enhanced field gives rise to local second-harmonic (SH) generation at the tip surface thereby creating a highly confined photon source. A theoretical model for the excitation and emission of SH radiation at the tip is developed and it is found that this source can be represented by a single on-axis oscillating dipole. The model is experimentally verified by imaging the spatial field distribution of strongly focused laser modes
Electrical excitation of surface plasmons
We exploit a plasmon mediated two-step momentum downconversion scheme to
convert low-energy tunneling electrons into propagating photons. Surface
plasmon polaritons (SPPs) propagating along an extended gold nanowire are
excited on one end by low-energy electron tunneling and are then converted to
free-propagating photons at the other end. The separation of excitation and
outcoupling proofs that tunneling electrons excite gap plasmons that
subsequently couple to propagating plasmons. Our work shows that electron
tunneling provides a non-optical, voltage-controlled and low-energy pathway for
launching SPPs in nanostructures, such as plasmonic waveguide
In-plane remote photoluminescence excitation of carbon nanotube by propagating surface plasmon
In this work, we demonstrate propagating surface plasmon polariton (SPP) coupled photoluminescence (PL) excitation of single-walled carbon nanotube (SWNT). SPPs were launched at a few micrometers from individually marked SWNT, and plasmon-coupled PL was recorded to determine the efficiency of this remote in-plane addressing scheme. The efficiency depends upon the following factors: (i) longitudinal and transverse distances between the SPP launching site and the location of the SWNT and (ii) orientation of the SWNT with respect to the plasmon propagation wave vector (k SPP). Our experiment explores the possible integration of carbon nanotubes as a plasmon sensor in plasmonic and nanophotonic devices
Spontaneous hot-electron light emission from electron-fed optical antennas
Nanoscale electronics and photonics are among the most promising research
areas providing functional nano-components for data transfer and signal
processing. By adopting metal-based optical antennas as a disruptive
technological vehicle, we demonstrate that these two device-generating
technologies can be interfaced to create an electronically-driven self-emitting
unit. This nanoscale plasmonic transmitter operates by injecting electrons in a
contacted tunneling antenna feedgap. Under certain operating conditions, we
show that the antenna enters a highly nonlinear regime in which the energy of
the emitted photons exceeds the quantum limit imposed by the applied bias. We
propose a model based upon the spontaneous emission of hot electrons that
correctly reproduces the experimental findings. The electron-fed optical
antennas described here are critical devices for interfacing electrons and
photons, enabling thus the development of optical transceivers for on-chip
wireless broadcasting of information at the nanoscale
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