## Time-domain numerical modeling of heat generation

in metallic nanoparticles

Although losses in metal are viewed as a serious drawback in
many plasmonics experiments, thermoplasmonics is the field of
physics that tries to take advantage of the latter. Indeed, the
strong field enhancement obtained in nanometallic structures
lead to a localized temperature increase in its vicinity,
leading to interesting photothermal effects. Therefore,
metallic nanoparticles may be used as heat sources that can be
easily integrated in various environments. This is especially
appealing in the field of nanomedecine and can for example be
used for diagnosis purposes or nanosurgery to cite but just a
few. Due to the various scales and phenomena that come into
play, accurate numerical modeling is challenging. Laser
illumination first excites a plasmon oscillation (reaction of
the electrons of the metal) that relaxes to a thermal
equilibrium and in turn excites the metal lattice (phonons).
The latter is then responsible for heating the surroundings. A
relevant modeling approach thus consists in describing the
electron-phonon coupling through the evolution of their
respective temperature. Maxwell's equations are then coupled to
a set of coupled nonlinear hyperbolic equations for the
temperatures of respectively electrons, phonons and environment.
The nonlinearities and the different time scales at which each
thermalization occurs make the numerical approximation of these
equations quite challenging. We develop a suitable numerical
framework based on high order discontinuous Galerkin methods for
studying thermoplasmonics in the time-domain setting.