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Amplified Photothermal Phase Modulation for Carbon Dioxide Detection by Operating a Dual-Mode Interferometer at
Yingzhen Hong1,2, Feifan Chen1,2, Haihong Bao1,2
1Department of Electrical Engineering and Photonics Research Institute, The Hong Kong Polytechnic University, Kowloon 999077, Hong Kong, China.
Analytical Chemistry
|February 16, 2023
Summary
This study enhances trace gas detection using photothermal interferometry. A novel dual-mode fiber interferometer achieves ultrasensitive carbon dioxide detection down to 1 part-per-billion.
Area of Science:
- Spectroscopy
- Optical sensing
- Environmental monitoring
Background:
- Photothermal interferometry is a sensitive technique for trace gas detection.
- Current laser spectroscopic sensors lack the precision for some high-demand applications.
Purpose of the Study:
- To demonstrate an ultrasensitive carbon dioxide detection method using optical phase-modulation amplification.
- To improve the sensitivity of phase modulation-based sensors.
Main Methods:
- Operating a dual-mode optical fiber interferometer at destructive interference.
- Utilizing a 50 cm dual-mode hollow-core fiber for signal amplification.
Main Results:
- Achieved amplification of photothermal phase modulation by a factor of nearly 20.
- Enabled carbon dioxide detection down to 1 part-per-billion (ppb).
- Demonstrated a dynamic range exceeding 7 orders of magnitude.
Conclusions:
- Optical phase-modulation amplification in a dual-mode fiber interferometer significantly enhances sensitivity.
- The technique offers a compact and simple configuration for improved gas sensing.
- This method is suitable for high-precision applications requiring ultrasensitive detection.
