Quasi-Simultaneous Sensitive Detection of Two Gas Species by Cavity-Ringdown Spectroscopy with Two Lasers
We developed a cavity ringdown spectrometer by utilizing a step-scanning and dithering method for matching laser wavelengths to optical resonances of an optical cavity. Our approach is capable of working with two and more lasers for quasi-simultaneous measurements of multiple gas species. The develo...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/fd9164a454704eddba8d7bd58e72113f |
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| Sumario: | We developed a cavity ringdown spectrometer by utilizing a step-scanning and dithering method for matching laser wavelengths to optical resonances of an optical cavity. Our approach is capable of working with two and more lasers for quasi-simultaneous measurements of multiple gas species. The developed system was tested with two lasers operating around 1654 nm and 1658 nm for spectral detections of <sup>12</sup>CH<sub>4</sub> and its isotope <sup>13</sup>CH<sub>4</sub> in air, respectively. The ringdown time of the empty cavity was about 340 µs. The achieved high detection sensitivity of a noise-equivalent absorption coefficient was 2.8 × 10<sup>−11</sup> cm<sup>−1</sup> Hz<sup>−1/2</sup> or 1 × 10<sup>−11</sup> cm<sup>−1</sup> by averaging for 30 s. The uncertainty of the high precision determination of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi mathvariant="sans-serif">δ</mi><mn>13</mn></msup><msub><mi>CH</mi><mn>4</mn></msub></mrow></semantics></math></inline-formula> in air is about 1.3‰. Such a system will be useful for future applications such as environmental monitoring. |
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