Super-radiant and Sub-radiant Cavity Scattering by Atom Arrays

TL;DR

This study demonstrates collective enhancement and suppression of light scattering in atom arrays within an optical cavity, revealing controllable super-radiant and sub-radiant behaviors and atom-induced cavity shifts.

Contribution

It introduces a method to control collective light scattering in atom arrays inside a cavity, showing tunable super- and sub-radiant effects with precise atom positioning.

Findings

N^2 scaling of cavity photons with atom number for integer-wavelength spacing

Non-monotonic, sub-radiant cavity intensity for half-integer-wavelength spacing

Rayleigh scattering can be collectively enhanced or suppressed

Abstract

We realize collective enhancement and suppression of light scattered by an array of tweezer-trapped $^{87}$Rb atoms positioned within a strongly coupled Fabry-P\'{e}rot optical cavity. We illuminate the array with light directed transverse to the cavity axis, in the low saturation regime, and detect photons scattered into the cavity. For an array with integer-optical-wavelength spacing each atom scatters light into the cavity with nearly identical scattering amplitude, leading to an observed $N^2$ scaling of cavity photon number as the atom number increases stepwise from $N=1$ to $N=8$. By contrast, for an array with half-integer-wavelength spacing, destructive interference of scattering amplitudes yields a non-monotonic, sub-radiant cavity intensity versus $N$. By analyzing the polarization of light emitted from the cavity, we find that Rayleigh scattering can be collectively enhanced or suppressed with respect to Raman scattering. We observe also that atom-induced shifts and broadenings of the cavity resonance are precisely tuned by varying the atom number and positions. Altogether, tweezer arrays provide exquisite control of atomic cavity QED spanning from the single- to the many-body regime.