Measurement of the Fundamental Thermal Noise Limit in a Cryogenic Sapphire Frequency Standard Using Bimodal Maser Oscillations

2008/06/09 by Karim Benmessaï, Karim Benmessai, Daniel Lloyd Creedon +8 · 1 citation
Physics and Astronomy · #Advanced Frequency and Time Standards #Atomic and Subatomic Physics Research #Radioactive Decay and Measurement Techniques #physics.atom-ph #physics.optics

paper · pdf · doi:10.1103/physrevlett.100.233901

published as PRL 100, 233901 (2008) · Published in PRL 100, 233901 (2008)

openalex publication_date 2008/06/09 · arxiv created 2008/07/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04

Abstract

We report observations of the Schawlow-Townes noise limit in a cryogenic sapphire secondary frequency standard. The effect causes a fundamental limit to the frequency stability, and was measured through the novel excitation of a bimodal maser oscillation of a Whispering Gallery doublet at 12.04 GHz. The beat frequency of 10 kHz between the oscillations enabled a sensitive probe for this measurement of fractional frequency instability of 10(-14) tau(-1/2) with only 0.5 pW of output power.

Citations

• Thermal Agitation of Electric Charge in Conductors
• On the relative motion of the Earth and the luminiferous ether

Cited by

• High Q-factor sapphire whispering gallery mode microwave resonator at single photon energies and millikelvin temperatures

Related

• Frequency Stability Measurement of Cryogenic Sapphire Oscillators with a Multichannel Tracking DDS and the Two-Sample Covariance
• Characterization of the individual short-term frequency stability of Cryogenic Sapphire Oscillators at the 1e-16 level
• Low Noise Microwaves for Testing Fundamental Physics
• Stability measurements of microwave frequency synthesis with liquid helium cooled cryogenic sapphire oscillators
• Unprecedented High Long Term Frequency Stability with a Macroscopic Resonator Oscillator