A chip-scale atomic clock based on 87Rb with improved frequency stability.

Area of Science:

• Atomic Physics
• Microfabrication
• Metrology

Background:

• Atomic clocks are crucial for precise timekeeping and navigation.
• Microfabrication enables miniaturization of atomic clock components.
• Coherent Population Trapping (CPT) is a key technique for atomic clock operation.

Purpose of the Study:

• To demonstrate a microfabricated atomic clock physics package using 87Rb atoms.
• To evaluate the performance and stability of the 87Rb CPT atomic clock.
• To compare the 87Rb clock's performance against a previous cesium-based device.

Main Methods:

• Fabrication of a microchip atomic clock package.
• Utilizing coherent population trapping (CPT) on the D1 line of 87Rb atoms.
• Characterizing clock stability at short and long timescales.

Main Results:

• The 87Rb atomic clock package has a volume of 12 mm3 and consumes 195 mW of power.
• Achieved short-term instability of 4 x 10-11 / sqrt(tau).
• Demonstrated long-term stability with a drift of ~5 x 10-9 / day, significantly improved over Cs clocks.

Conclusions:

• The 87Rb CPT atomic clock offers superior short- and long-term stability compared to previous microfabricated Cs clocks.
• Increased resonance amplitude contributes to improved short-term stability.
• Reduced drift, potentially due to minimized chemical reactions, enhances long-term performance.