posted on 2024-01-17, 15:41authored byPuyuan He, Augustin Caillas, Guillaume Boulliard, Ismail Hamdi, Pascal Filloux, Marco Ravaro, Emmanuel Lhuillier, Aloyse Degiron
We
examine, in the time domain, the influence of Au antenna arrays
(i.e., metasurfaces) on thin films of near-infrared PbS nanocrystals
that mutually interact via Förster resonance energy transfer
(FRET). While the geometry and optical properties of the arrays have
a direct and sometimes spectacular impact on the transient photoluminescence
spectra of the emitters, we experimentally show that the decay rates
at any given wavelength are remarkably similar for all samples. This
observation is in stark contrast with the textbook case of individual
emitters weakly coupled to photonic structures. We show that FRET
plays two key roles in these experimentsfirst, it is more
efficient than other nonradiative energy transfers, including Joule
dissipation in the optical antennas, for most wavelengths; second,
it thermalizes the photocarriers of neighboring nanocrystals before
their recombination, making them behave as an effective semiconducting
material obeying a generalized form of Kirchhoff’s law.