  Effective cross-sections of nano-objects are fundamental properties that
determine their ability to interact with light. However, measuring them for
individual resonators directly and quantitatively remains challenging,
particularly because of the very low signals involved. Here, we experimentally
measure the thermal emission cross-section of metal-insulator-metal
nano-resonators using a stealthy hyperuniform distribution based on a
hierarchical Poisson-disk algorithm. In such distributions, there are no
long-range interactions between antennas, and we show that the light emitted by
the metasurface behaves as the sum of cross-sections of independent
nanoantennas, enabling direct retrieval of the single resonator contribution.
The emission cross-section at resonance is found to be of the order of
$\mathbf{\lambda_0^2/3}$, a value that is nearly three times larger than the
theroretical maximal absorption cross-section of a single particle but remains
smaller than the maximal extinction cross-section. This measurement technique
can be generalized to any single resonator cross-section, and we also apply it
here to the extinction cross-section.
