Related Experiment Video
Updated: Jan 21, 2026

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
Published on: April 25, 2019
Orthogonal Demodulation Pound-Drever-Hall Technique for Ultra-Low Detection Limit Pressure Sensing
Jinliang Hu1, Sheng Liu1, Xiang Wu1
1Key Lab for Micro and Nanophotonic Structures (Ministry of Education), Department of Optical Science and Engineering, School of Information Science and Engineering, Fudan University, Shanghai 200433, China.
Abstract:
We report on a novel optical microcavity sensing scheme by using the orthogonal demodulation Pound-Drever-Hall (PDH) technique. We found that larger sensitivity in a broad range of cavity quality factor (Q) could be obtained. Taking microbubble resonator (MBR) pressure sensing as an example, a lower detection limit than the conventional wavelength shift detection method was achieved. When the MBR cavity Q is about 105-106, the technique can decrease the detection limit by one or two orders of magnitude. The pressure-frequency sensitivity is 11.6 GHz/bar at wavelength of 850 nm, and its detection limit can approach 0.0515 mbar. This technique can also be applied to other kinds of microcavity sensors to improve sensing performance.
Related Concept Videos
The Hall Effect
Difference from Background: Limit of Detection
The LOD indicates the presence or absence...
Limiting Reactant
The Sense of Self: Reflected Self-Appraisal and Social Comparison
The Number e as a Limit
Introduction to Special Senses

