Related Experiment Video
Updated: May 18, 2026
12:18
Microwave Photonics Systems Based on Whispering-gallery-mode Resonators
Published on: August 5, 2013
Spherical-sapphire-based whispering gallery mode resonator thermometer.
1INRIM, Strada delle Cacce 91, 10135 Turin, Italy. lili.yu@polito.it
The Review of Scientific Instruments
|October 2, 2012
Summary
A new spherical sapphire resonator was developed for microwave thermometry. This novel thermometer demonstrates excellent performance, showing potential for precise temperature measurements across a wide range.
Area of Science:
- Physics
- Metrology
- Materials Science
Background:
- Whispering gallery mode (WGM) resonators offer high sensitivity for physical measurements.
- Sapphire crystals are known for their excellent dielectric properties and thermal stability.
- Accurate thermometry is crucial for various scientific and industrial applications.
Purpose of the Study:
- To develop and evaluate a novel microwave whispering gallery mode (WGM) resonator using a spherical sapphire crystal for thermometry.
- To investigate the temperature dependence of WGM frequencies in the sapphire resonator.
- To assess the metrological characteristics of the developed sapphire thermometer.
Main Methods:
- Fabrication of a spherical sapphire WGM resonator.
- Experimental study of WGM frequencies near 13.6 GHz and their temperature dependence.
- Evaluation of key metrological parameters: temperature sensitivity, frequency stability, repeatability, and resolution.
- Comparison with an existing dielectric thermometer (NIST SWGT).
Main Results:
- A novel spherical sapphire WGM resonator was successfully developed.
- The temperature dependence of WGM frequencies was characterized over the -40 °C to 85 °C range.
- A promising resonance with a loaded quality factor of 82,000 was identified and investigated.
- The thermometer exhibited good temperature sensitivity, stability, repeatability, and resolution.
Conclusions:
- The developed spherical sapphire WGM resonator shows significant potential as a high-performance thermometer.
- Its metrological characteristics suggest suitability for precise temperature measurements.
- Further research and comparison with established standards confirm its viability.
