Quantum-Enhanced Velocimetry with Doppler-Broadened Atomic Vapor

Area of Science:

• Atomic physics
• Quantum optics
• Metrology

Background:

• Traditional atomic ensemble velocity measurement relies on Doppler shift of single atoms, requiring narrow velocity distribution.
• This method is limited by the need for specific atomic ensemble preparation and detailed velocity distribution mapping.

Purpose of the Study:

• To develop a novel, highly sensitive method for measuring the center-of-mass (c.m.) velocity of an atomic ensemble.
• To overcome the limitations of traditional Doppler shift measurements by not requiring knowledge of the atomic velocity distribution.

Main Methods:

• Utilizing a dispersive measurement of light transmitted through a room-temperature atomic vapor cell.
• Employing electromagnetically induced transparency (EIT) with an auxiliary transition to enhance optical dispersion.
• Measuring the collective motion of atoms rather than individual atomic properties.

Main Results:

• Achieved a short-term sensitivity of 5.5 μm s⁻¹ Hz⁻¹/² for c.m. velocity measurement in a single shot.
• Demonstrated velocity sensing without prior knowledge of the atomic ensemble's velocity distribution.
• Improved measurement sensitivity by 3 orders of magnitude compared to previous techniques.

Conclusions:

• The developed dispersive measurement technique offers a significant advancement in atomic velocity sensing.
• This method enables precise c.m. velocity determination of atomic ensembles irrespective of their velocity distribution.
• The findings pave the way for designing compact and highly sensitive motional sensors utilizing thermal atomic vapors.