3.5-mu m high-resolution gas sensing employing a LiNbO3 QPM-DFG waveguide module
Diode laser technology coupled with a wavelength-conversion unit to produce mid-infrared narrow bandwidth laser light applicable to trace-gas detection and with the potential for high-resolution spectroscopy is described. Quasi-phase-matched difference-frequency generation (QPM-DFG) in a compact and...
| Main Authors: | , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2009
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| Summary: | Diode laser technology coupled with a wavelength-conversion unit to produce mid-infrared narrow bandwidth laser light applicable to trace-gas detection and with the potential for high-resolution spectroscopy is described. Quasi-phase-matched difference-frequency generation (QPM-DFG) in a compact and fibre-coupled periodically poled lithium niobate (PPLN) waveguide module mixing 1063 and 1525-nm radiations has been adopted for generating 34 μW of 3.5-μm wavelength laser light. Optical detection methods, including sensitive wavelength modulation spectroscopy and a rapid wavelength chirp technique, have been employed with a single-pass cell to investigate methane and formaldehyde absorption profiles around 2855 cm-1, as proof of principle experiments for high sensitivity and resolution spectroscopy on atmospherically important molecules. © 2008 Springer-Verlag. |
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