Pressure sensing with high-finesse monolithic buckled-dome microcavities

Area of Science:

• Optics and Photonics
• Materials Science
• Sensor Technology

Background:

• Fabry-Perot cavities are optical resonators used in various applications.
• Traditional Fabry-Perot pressure sensors often have limitations in sensitivity and finesse.
• Developing novel microscale sensors is crucial for advanced measurement applications.

Purpose of the Study:

• To introduce and characterize on-chip buckled-dome Fabry-Perot microcavities as novel pressure sensing elements.
• To investigate the relationship between external pressure and resonance wavelength shifts in these microcavities.
• To evaluate the sensitivity and resolution of these microcavity-based pressure sensors.

Main Methods:

• Fabrication of sealed, on-chip buckled-dome Fabry-Perot microcavities using a controlled thin-film buckling process.
• Characterization of optical modes and optical fiber coupling capabilities (finesse >10^3).
• Experimental measurement of resonance wavelength shifts in response to applied external pressure.

Main Results:

• Demonstrated stable optical modes with high finesse (>10^3), suitable for single-mode fiber coupling.
• Observed pressure-induced deflection of the buckled upper mirror, causing measurable resonance wavelength shifts.
• Achieved high sensitivity (∼1 nm/kPa) due to the low thickness (<2 µm) of the buckled mirror and a resolution of ∼10 Pa.
• Experimental results showed good agreement with theoretical predictions.

Conclusions:

• On-chip buckled-dome Fabry-Perot microcavities are effective and highly sensitive pressure sensing elements.
• These microcavities offer potential advantages over traditional low-finesse, quasi-planar Fabry-Perot pressure sensors.
• The demonstrated sensitivity and resolution highlight the potential of this technology for advanced pressure metrology.