Strong Purcell Effect on a Neutral Atom Trapped in an Open Fiber Cavity

Area of Science:

• Atomic Physics
• Quantum Optics
• Cavity Quantum Electrodynamics (cQED)

Background:

• Optically trapped neutral atoms are crucial for quantum information processing.
• Strong coupling between atoms and optical cavities enhances light-matter interactions.
• Fiber cavities offer robust and efficient interfaces for quantum technologies.

Purpose of the Study:

• To investigate the Purcell enhancement of an atom coupled to a fiber cavity.
• To quantify the efficiency of fluorescence emission into the cavity mode.
• To explore the potential of this system for photonic interfaces.

Main Methods:

• Utilizing an optically trapped Rubidium-87 atom.
• Strongly coupling the atom to a high-finesse fiber cavity.
• Measuring atomic fluorescence and photon statistics under laser illumination.
• Analyzing the photon autocorrelation function to confirm sub-Poissonian statistics and Purcell enhancement.

Main Results:

• Observed a sixfold Purcell broadening of the Rubidium-87 D2 line.
• Demonstrated up to 90% of atomic fluorescence coupled into the cavity mode.
• Confirmed sub-Poissonian statistics of cavity output and enhanced atomic decay rate.
• Identified photon leakage as the dominant field decay channel (κ≈2π×50 MHz).

Conclusions:

• Strong atom-fiber cavity coupling enables efficient channeling of atomic fluorescence.
• The observed Purcell enhancement and sub-Poissonian statistics are key indicators of high-quality light-matter interaction.
• This system provides a high-bandwidth, fiber-coupled platform for quantum memories and single-photon sources.