We study the collective response of a dense atomic sample to light essentially exactly using classical-electrodynamics simulations. In a homogeneously broadened atomic sample there is no overt Lorentz-Lorenz local field shift of the resonance, nor a collective Lamb shift. However, the addition of inhomogeneous broadening restores the usual mean-field phenomenology.
DOI:https://doi.org/10.1103/PhysRevLett.112.113603
© 2014 American Physical Society
Optical depth versus detuning in a homogeneously broadened sample for sample thicknesses , 0.5, 1.0, and 2.0, from bottom to top; the corresponding atom numbers are , 256, 512, and 1024. The dashed vertical line shows where the center of the line would be if the naive Lorentz-Lorenz shift applied.
Reuse & PermissionsLeft: Optical depth of the sample with thickness , and, hence, atoms, as a function of the detuning for a sample with the inhomogeneous linewidth . This numerical experiment (solid red line) is an average of 1024 samples, the fit with a Voigt profile (dashed black line) has the parameters , , and . Right: The shift of the absorption line plotted as a function of the thickness of the sample as solid circles. The statistical error bars are smaller than the size of the circles. Also shown as a solid line is the collective Lamb shift, Eq. (2), and as a dashed line a vertically translated version of Eq. (2) fitted to the numerical data points with .
Reuse & Permissions
