A 44-cm3 physics package for the high-performance pulsed optically pumped atomic clock.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Metrology and Measurement Science

Background:

• Pulsed optically pumped (POP) atomic clocks offer high frequency stability but are typically large.
• Miniaturization of POP atomic clocks presents significant engineering challenges.

Purpose of the Study:

• To design and characterize a miniaturized physics package for a POP atomic clock.
• To analyze the performance metrics of the compact atomic clock, including stability and noise sources.

Main Methods:

• Designed a compact physics package with a magnetron microwave cavity and a small vapor cell (1.3 cm internal diameter).
• Analyzed the Zeeman transition spectrum to confirm microwave cavity resonance (TE011-like mode).
• Quantitatively assessed relaxation times, linewidth, and noise using a low-noise testbed.

Main Results:

• Achieved population and coherence relaxation times of 3.16(0.16) ms and 2.97(0.03) ms at 333 K, consistent with theoretical predictions.
• Observed a Ramsey signal contrast of 35% and a linewidth of 192 Hz.
• The miniaturized physics package has a volume of approximately 44 cm³, including magnetic shielding.
• Measured short-term frequency stability of 4.8 × 10⁻¹³τ⁻¹/².

Conclusions:

• The developed miniaturized POP atomic clock demonstrates promising performance in frequency stability.
• The primary limitation for short-term stability is identified as the relative intensity noise of the laser system.
• This work paves the way for more compact and portable high-performance atomic clocks.