Loaded Microwave Cavity for Compact Vapor-Cell Clocks.

Area of Science:

• Physics
• Electrical Engineering
• Atomic Clocks

Background:

• Microwave interrogation in vapor-cell devices offers stable frequency references.
• Miniaturization of atomic clocks requires optimization of the physics package, including the microwave cavity and atomic reservoir.

Purpose of the Study:

• To present a compact cavity-cell assembly for miniaturized microwave atomic clocks.
• To strongly reduce the size of the atomic clock core while maintaining high short-term stability.

Main Methods:

• Design and characterization of a dielectric-loaded cylindrical resonator with a 35 cm³ external volume.
• Finite-element calculations to analyze microwave field uniformity and atom-field coupling.
• Experimental characterization of thermal sensitivity and integration into a rubidium clock setup.

Main Results:

• A compact cavity-cell assembly with a 0.9 cm³ inner volume was achieved.
• High short-term stability (σy(τ) ≤ 5×10⁻¹³ τ⁻¹/2) was maintained.
• Preliminary spectroscopy results demonstrated compatible clock signals for targeted performances.

Conclusions:

• The dielectric-loaded cavity approach is a viable design for miniaturized microwave clocks.
• The proposed design enables significant size reduction of the atomic clock core.
• The technology supports the development of compact and robust frequency references.