Collective radiative propieties of ordered atomic chains

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2021, Tutora: Maria Moreno CardonerWe study the optical properties of an ordered atomic array when the interparticle distance is smaller than the light wavelength, for which collective effects arising from light-induced dipole-dipole interactions become relevant. In this case the scattered fields by the atoms interfere and can lead to an enhanced or suppressed spontaneous emission of photons corresponding to superradiance or subradiance, respectively. For a single excitation the system can be described in terms of collective eigenmodes, which have a modified decay rate and frequency shift compared to a single atom. By using exact diagonalization we derive the collective decay rates of an atomic array coupled to a nanophotonic waveguide and also in free space, whose atoms are transversally polarized to the atomic chain. We then study an application that takes advantage of the collective decay and subradiance arising in atomic array