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Tunable Diode Laser Absorption Spectroscopy of Carbon Monoxide Around 2.35 microm
Applied Optics
|February 28, 2008
Summary
New GaInSbAs/GaSb lasers enable tunable diode laser absorption spectroscopy near 2.35 µm. These lasers can detect trace carbon monoxide, showing potential for portable pollutant sensors.
Area of Science:
- Materials Science
- Spectroscopy
- Environmental Monitoring
Background:
- Development of advanced laser sources for sensitive gas detection is crucial.
- Tunable diode laser absorption spectroscopy (TDLAS) offers high selectivity and sensitivity.
- Room-temperature operation is desirable for practical, portable sensing applications.
Purpose of the Study:
- To demonstrate the application of novel GaInSbAs/GaSb multiple-quantum-well (MQW) lasers for TDLAS.
- To investigate the performance of these lasers for detecting carbon monoxide (CO).
- To assess the potential of these lasers in developing portable trace-pollutant sensors.
Main Methods:
- Fabrication and characterization of GaInSbAs/GaSb MQW lasers operating near 2.35 µm.
- Implementation of tunable diode laser absorption spectroscopy (TDLAS) using these lasers.
- Utilizing low-frequency wavelength-modulation spectroscopy (WMS) with an astigmatic multipass cell for enhanced detection sensitivity.
Main Results:
- Successful operation of GaInSbAs/GaSb MQW lasers near room temperature.
- Achieved continuous current tuning over a frequency range exceeding 150 GHz.
- Direct absorption measurements of carbon monoxide (CO) R-branch lines were performed.
- Detection of CO at concentrations as low as 0.3 ppmv at 100 Torr was demonstrated.
Conclusions:
- Novel GaInSbAs/GaSb MQW lasers are suitable for TDLAS applications near 2.35 µm.
- The developed spectroscopic system shows high sensitivity for trace CO detection.
- These lasers hold significant potential for the development of portable, low-cost trace-pollutant sensors.
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