High-Sensitivity Multitrace Gas Simultaneous Detection Based on an All-Optical Miniaturized Photoacoustic Sensor

Area of Science:

• Optics and Photonics
• Gas Sensing Technology
• Spectroscopy

Background:

• Miniaturized sensors are crucial for in-situ gas analysis.
• Simultaneous detection of multiple gases requires sophisticated sensor technology.
• Photoacoustic spectroscopy offers high sensitivity for gas detection.

Purpose of the Study:

• To develop an all-optical, miniaturized photoacoustic sensor for simultaneous multigas detection.
• To achieve high sensitivity and selectivity for target gases in a compact device.
• To demonstrate the sensor's capability in a laser photoacoustic spectroscopy system.

Main Methods:

• Fabrication of a miniaturized photoacoustic cell (36 μL) using a copper tube and silica cantilever.
• Integration of four single-mode fibers for laser excitation and signal probing.
• Utilizing distributed feedback lasers at 1532.8, 1576.3, and 1653.7 nm for acetylene, hydrogen sulfide, and methane.
• Employing a high-speed spectrometer as a demodulator for simultaneous measurements.

Main Results:

• Achieved minimum detection limits of 4.8 ppb for acetylene (C2H2), 162 ppb for hydrogen sulfide (H2S), and 16.6 ppb for methane (CH4).
• Demonstrated simultaneous measurement capability for the target gases.
• The sensor volume is 71 cubic millimeters, highlighting its miniaturization.

Conclusions:

• The developed all-optical miniaturized photoacoustic sensor enables high-sensitivity, simultaneous multigas detection.
• The sensor's compact size and performance show potential for various applications requiring trace gas analysis.
• This technology advances the field of portable and efficient gas sensing systems.