Implementation of Cavity Squeezing of a Collective Atomic Spin

Abstract

We squeeze unconditionally the collective spin of a dilute ensemble of laser-cooled superscript 87]Rb atoms using their interaction with a driven optical resonator. The shape and size of the resulting spin uncertainty region are well described by a simple analytical model [M. H. Schleier-Smith, I. D. Leroux, and V. Vuletić, arXiv:0911.3936 [Phys. Rev. A (to be published)]] through 2 orders of magnitude in the effective interaction strength, without free parameters. We deterministically generate states with up to 5.6(6) dB of metrologically relevant spin squeezing on the canonical [superscript 87]Rb hyperfine clock transition.