Spectral line

Quantum mechanics

Discrete dipole approximation

Embedded system

Scattering

Atomic physics

Computer science

Wavelength

Ultracold atom

Light scattering

Physics

Dipole

Optics

Molecular physics

Resonance (particle physics)

Chain (unit)

Atom (system on chip)

Stark effect

Quantum

Light field

Physical Review Letters

We experimentally study resonant light scattering by a one-dimensional randomly filled chain of cold two-level atoms. By a local measurement of the light scattered along the chain, we observe constructive interferences in light-induced dipole-dipole interactions between the atoms. They lead to a shift of the collective resonance despite the average interatomic distance being larger than the wavelength of the light. This result demonstrates that strong collective effects can be enhanced by structuring the geometrical arrangement of the ensemble. We also explore the high intensity regime where atoms cannot be described classically. We compare our measurement to a mean-field, nonlinear coupled-dipole model accounting for the saturation of the response of a single atom.

Collective Shift in Resonant Light Scattering by a One-Dimensional Atomic Chain