Observation of Motion Dependent Nonlinear Dispersion with Narrow Linewidth Atoms in an Optical Cavity

Abstract

As an alternative to state-of-the-art laser frequency stabilisation using ultra-stable cavities, it has been proposed to exploit the non-linear effects from coupling of atoms with a narrow transition to an optical cavity. Here we have constructed such a system and observed non-linear phase shifts of a narrow optical line by strong coupling of a sample of strontium-88 atoms to an optical cavity. The sample temperature of a few mK provides a domain where the Doppler energy scale is several orders of magnitude larger than the narrow linewidth of the optical transition. This makes the system sensitive to velocity dependent multi-photon scattering events (Dopplerons) that affect the cavity field transmission and phase. By varying the number of atoms and the intra-cavity power we systematically study this non-linear phase signature which displays roughly the same features as for much lower temperature samples. This demonstration in a relatively simple system opens new possibilities for alternative routes to laser stabilization at the sub 100 mHz level and superradiant laser sources involving narrow line atoms. The understanding of relevant motional effects obtained here has direct implications for other atomic clocks when used in relation with ultranarrow clock transitions.

arXiv comment9 pages (including 4 pages of Supplemental Information), 6 figures. Updated to correspond to the published version

References in corpus (16)

• An Optical Lattice Clock with Accuracy and Stability at the $10^{-18}$ Level
• Frequency Comparison of Two High-Accuracy Al+ Optical Clocks
• An atomic clock with $10^{-18}$ instability
• A sub-40 mHz linewidth laser based on a silicon single-crystal optical cavity
• Making optical atomic clocks more stable with $10^{-16}$ level laser stabilization
• Prospects for a mHz-linewidth laser
• Experimenting an optical second with strontium lattice clocks
• Ultrastable lasers based on vibration insensitive cavities
• Comparison of Two Independent Sr Optical Clocks with 1e-17 Stability at 10^3 s
• A quantum many-body spin system in an optical lattice clock
• Steady-state superradiance with alkaline earth atoms
• Thermal noise in optical cavities revisited
• Production of quantum degenerate strontium gases: Larger, better, faster, colder
• Optical spectrum analyzer with quantum limited noise floor
• A superradiant clock laser on a magicwavelength optical lattice
• Extreme non-linear response of ultra-narrow optical transitions in cavity QED for laser stabilization

Cited by in corpus (13)

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• Magnetically-Induced Optical Transparency on a Forbidden Transition in Strontium for Cavity-Enhanced Spectroscopy
• Strong Coupling on a Forbidden Transition in Strontium and Nondestructive Atom Counting
• Non-linear Spectroscopy of Sr Atoms in an Optical Cavity for Laser Stabilization
• Collective Excitation Dynamics of a Cold Atom Cloud
• A mid-infrared magneto-optical trap of metastable strontium for an optical lattice clock
• Dynamics of bad-cavity enhanced interaction with cold Sr atoms for laser stabilization
• Prospects for a bad cavity laser using a large ion crystal
• Exploration of the magnetic-field-induced $5s5p$~${}^3{P}_0$~-~$5s^2$~${}^1{S}_0$ forbidden transition in bosonic Sr atom
• Observation of photon recoil effects in single-beam absorption spectroscopy with an ultracold strontium gas
• Coupling atoms to cavities with narrow linewidth optical transitions: Applications to frequency metrology