A cold-atom beam clock based on coherent population trapping.

Area of Science:

• Atomic Physics
• Quantum Optics
• Metrology

Background:

• Atomic clocks are essential for modern technology and scientific research.
• Developing more stable and accurate atomic clocks is an ongoing challenge.

Purpose of the Study:

• To present the design and performance of a novel atomic clock.
• To demonstrate the effectiveness of using cold atoms and Ramsey interrogation for improved clock stability.

Main Methods:

• Utilized a beam of cold Rubidium-87 (⁸⁷Rb) atoms generated by a 2D⁺-magnetooptical trap.
• Employed spatially separated Ramsey coherent population trapping interrogation on the ⁸⁷Rb D2 line.
• Implemented a counter-propagating σ⁺-σ⁻ probing scheme for optical field interrogation.

Main Results:

• Achieved narrow Ramsey fringes due to the use of cold atoms, even with a small interrogation zone separation (4.6 cm).
• The atomic clock demonstrated a short-term stability of 3 × 10⁻¹¹/√τ.
• The hyperfine clock transition at 6.834 GHz was successfully interrogated.

Conclusions:

• Cold atom techniques combined with Ramsey interrogation offer a viable path to high-performance atomic clocks.
• The presented atomic clock design shows promise for applications requiring precise timekeeping.