Home > Research > Publications & Outputs > Optical response of atom chains beyond the limi...

Associated organisational unit


Text available via DOI:

View graph of relations

Optical response of atom chains beyond the limit of low light intensity: The validity of the linear classical oscillator model

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Article number023273
<mark>Journal publication date</mark>3/06/2020
<mark>Journal</mark>Physical Review Research
Issue number2
Number of pages12
Publication StatusPublished
<mark>Original language</mark>English


Atoms subject to weak coherent incident light can be treated as coupled classical linear oscillators, supporting subradiant and superradiant collective excitation eigenmodes. We identify the limits of validity of this linear classical oscillator model at increasing intensities of the drive by solving the quantum many-body master equation for coherent and incoherent scattering from a chain of trapped atoms. We show that deviations from the linear classical oscillator model depend sensitively on the resonance linewidths υα of the collective eigenmodes excited by light, with the intensity at which substantial deviation occurs scaling as a power law of υα . The linear classical oscillator model then becomes inaccurate at much lower intensities for subradiant collective excitations than superradiant ones, with an example system of seven atoms resulting in critical incident light intensities differing by a factor of 30 between the two cases. By individually exciting eigenmodes, we find that this critical intensity has a υ2.5 scaling for narrower resonances and more strongly interacting systems, while it approaches α a υα3 scaling for broader resonances and when the dipole-dipole interactions are reduced. The υα3 scaling also corresponds to the semiclassical result whereby quantum fluctuations between the atoms have been neglected. We study both the case of perfectly mode-matched drives and the case of standing-wave drives, with significant differences between the two cases appearing only at very subradiant modes and positions of Fano resonances.