Master 2: International Centre for Fundamental Physics
INTERNSHIP PROPOSAL
Laboratory name: Laboratoire de Physique des Solides
CNRS identification code: UMR8502
Internship director’surnames: Julien BASSET and Julien GABELLI
E-mail: Julien.basset@u-psud.fr, Julien.gabelli@u-psud.fr
Phone numbers: 0033169158011, 0033169155365
Web page: https://www.equipes.lps.u-psud.fr/ns2/
Internship location: Laboratoire de Physique des Solides
Université Paris Sud- Groupe Nanostructures à la Nanosecondes
Bat 510
91405 Orsay Cedex
Thesis possibility after internship:
YES
Funding: YES/NO
Quantum statistics of surface plasmons excited by a tunnel junction
Subject : When a voltage of a few volts is applied between two metals separated by a thin
insulating barrier, a tunnel current flows. This well-known electrical phenomenon is accompanied
by another optical one: the generation of light. The emitted light is broadband and can be seen as
the radiation due to the high frequency component of current fluctuations. In a tunnel junction,
these fluctuations are linked to the discrete nature of the electron, the shot noise.
Up-to-date it is known that photon emission in tunnel junctions is related to the
excitation, by electrons, of non-radiative modes called surface plasmon-polaritons. The coupling
between the plasmons located at the metal/air interface and the far field photons is subsequently
realized by scattering on surface roughness. This second step is however quite ineffective such
that the number of emitted photons by unit of electron varies from 10-4 to 10-6 in the optical range
( = 0.5-1.5μm). This makes the optical measurements difficult to realize though doable with stateof-the-art photon detectors.
The goal of this internship and eventually PhD will be to overcome the problem related
to plasmon/photon conversion by realizing a direct near-field measurement of plasmons. To this
end we will use nanoscale superconducting detectors placed on-chip as sketched in figure 1. By
directly studying the relationship between the quantum statistics of current fluctuations in a
tunnel junction and the resulting plasmon emission, one expect to determine if such statistics
can be imprinted on plasmons. This technological development could lead the way to a new
electrically driven quantum source of plasmons.
Fig 1: Proposed design geometry for on-chip emission, propagation and detection of surface
plasmon-polaritons.
Condensed Matter Physics: YES
Macroscopic Physics and complexity: NO
Quantum Physics:
YES
Theoretical Physics:
NO