Difference frequency generation in periodically poled lithium niobate and its use in the detection of atmospheric methane
Continuous wave mid-infrared radiation at 3.36 μm (power ≈ 18 μW) has been produced by difference frequency generation of the fundamental of a YAG laser at 1064 nm (220 mW) with a fibre pigtailed DFB diode laser operating at 1560 nm (50 mW) in periodically poled lithium niobate. The idler radiation...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2004
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| Summary: | Continuous wave mid-infrared radiation at 3.36 μm (power ≈ 18 μW) has been produced by difference frequency generation of the fundamental of a YAG laser at 1064 nm (220 mW) with a fibre pigtailed DFB diode laser operating at 1560 nm (50 mW) in periodically poled lithium niobate. The idler radiation has been used to make real-time measurements of ambient methane present in our laboratory using wavelength modulation spectroscopy via the P(4) multiplet transitions within the ν 3 band. We demonstrate a minimum detectable concentration of 47 ppb over a path length of 0.71 m in a 1 s observation time. Measurements of the pressure broadening and shift parameters for these lines are presented for methane in the presence of air, nitrogen and argon. © 2004 Elsevier B.V. All rights reserved. |
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