  We observe anomalous visible to near-infrared electromagnetic radiation
emitted from electrically driven atomic-size point contacts. We show that the
number of photons released strongly depends on the quantized conductance steps
of the contact. Counter-intuitively, the light intensity features an
exponential decay dependence with the injected electrical power. We propose an
analytical model for the light emission considering an out-of-equilibrium
electron distribution. We treat photon emission as bremsstrahlung process
resulting from hot electrons colliding with the metal boundary and a find
qualitative accord with the experimental data.
