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Asymmetric Tongs Induced Frequency Splitting Achieving Simultaneous Two-Component Gas Sensing with a Single Quartz
Shunda Qiao1, Ziheng Lv1, Bangyu Liu1,2
1National Key Laboratory of Laser Spatial Information, Harbin Institute of Technology, Harbin 150001, China.
ACS Sensors
|July 22, 2026
Summary
This study introduces a novel dual-gas sensor using an asymmetric quartz tuning fork (AQTF) for simultaneous methane and acetylene detection. The sensor achieves high sensitivity, reaching parts-per-billion detection limits for both gases.
Area of Science:
- Spectroscopy
- Chemical Sensing
- Materials Science
Background:
- Accurate and sensitive detection of multiple gases is crucial for environmental monitoring and industrial safety.
- Existing methods for simultaneous gas detection often involve complex instrumentation or multiple sensors.
- Light-induced thermoelastic spectroscopy (LITES) offers a sensitive approach for gas analysis.
Purpose of the Study:
- To develop a novel, highly sensitive LITES-based sensor for simultaneous detection of two gases using a single asymmetric quartz tuning fork (AQTF).
- To investigate the resonance characteristics and modal behavior of the AQTF for dual-gas sensing applications.
- To demonstrate the sensor's performance for simultaneous methane (CH4) and acetylene (C2H2) detection.
Main Methods:
- Fabrication of an AQTF from a standard quartz tuning fork (QTF) using mechanical assembly.
- Theoretical derivation and finite-element analysis of the AQTF's resonant frequency and modal behavior.
- Implementation of a LITES system with a multipass cell (40 m path length) and a transimpedance amplifier for signal detection.
- Optimization of integration time to achieve minimum detection limits.
Main Results:
- The AQTF exhibited clear resonance frequency splitting into two independent, mutually non-interfering in-plane symmetric vibration modes.
- Simultaneous detection of methane (CH4) and acetylene (C2H2) was successfully demonstrated using the single AQTF sensor.
- With a 200 s integration time, minimum detection limits of 65.72 ppb for CH4 and 19.85 ppb for C2H2 were achieved.
Conclusions:
- The developed AQTF is a foundational element for creating single-sensor, simultaneous dual-gas detection systems.
- The LITES-based sensor offers high sensitivity and low detection limits for key gases like methane and acetylene.
- This technology holds promise for advancements in gas sensing applications requiring simultaneous multi-component analysis.
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