| Autor: |
Bing, Chen, Ze-yi, Zhou, Peng, Kang, An-wen, Liu, Shui-rning, Hu |
| Rok vydání: |
2015 |
| Zdroj: |
Guang pu xue yu guang pu fen xi = Guang pu. 35(4) |
| ISSN: |
1000-0593 |
| Popis: |
A cavity ring-down spectrometer (CRDS) was built based on telecom distributed feedback (DFB) diode lasers. The ring down cavity was formed by mirrors of 99. 997% reflectivity with a separation of 130 cm, with an empty ring down time of about 150 µs. A minimum detectable absorption coefficient of 5 x 10(-12) cm(-1) was obtained by averaging about 1,000 recorded spectra. The ring down cavity is thermo-isolated, and used as an interferometer to calibrate the recorded spectrum. A feedback control scheme was applied to step scan the laser frequency, successively matching each of the longitudinal modes of the cavity. By measuring the CO contents in a standard gas sample, the quantitative capability of the CRDS instrument was demonstrated, and a CO detection limit of 4 ppb was achieved. The instrument was applied to monitor the CO concentration in ambient air. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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