Observation of squeezing in phase-dependent resonance fluorescence

H. M. Castro-Beltrán

H. J. Carmichael

We present an experimental realization of resonance fluorescence in squeezed vacuum.We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier.We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields.Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys.Rev. Lett.58, 2539 (1987)], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.

Matthew J. Collett, Daniel F. Walls, P. Zoller

Samir Bali

Phase-sensitive detection of resonance fluorescence, i.e., allowing the light emitted from an atom which is undergoing Rabi oscillations in free space to interfere with a coherent local oscillator (LO) beam, has drawn considerable attention throughout the history of quantum optics. Recently, phase-sensitive squeezing spectra for single-atom resonance fluorescence were observed for the first time using strongly-driven long-lived atoms. A measurement of phase-sensitive intensity correlations for this system will be presented. Using physical arguments I will construct the phase-sensitive two-time intensity autocorrelation function, and elucidate the role played by quantum fluctuations in phase-dependent resonance fluorescence.

Nikolay N. Bogolubov, A.S. Shumovsky, Tran Quang

D. M. Toyli, Andrew Eddins, Samuel Boutin +6 more

We present an experimental realization of resonance fluorescence in squeezed vacuum.We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier.We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields.Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys.Rev. Lett.58, 2539 (1987)], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.