| Autor: |
Harald, Moser, Andreas, Genner, Johannes, Ofner, C, Schwarzer, Gottfried, Strasser, Bernhard, Lendl |
| Rok vydání: |
2016 |
| Zdroj: |
Optics express. 24(6) |
| ISSN: |
1094-4087 |
| Popis: |
The present work reports on the first application of a ring-cavity-surface-emitting quantum-cascade laser (RCSE-QCL) for sensitive gas measurements. RCSE-QCLs are promising candidates for optical gas-sensing due to their single-mode, mode-hop-free and narrow-band emission characteristics along with their broad spectral coverage. The time resolved down-chirp of the RCSE-QCL in the 1227-1236 cmsup-1/sup(8.15-8.09 µm) spectral range was investigated using a step-scan FT-IR spectrometer (Bruker Vertex 80v) with 2 ns time and 0.1 cmsup-1/supspectral resolution. The pulse repetition rate was set between 20 and 200 kHz and the laser device was cooled to 15-17°C. Employing 300 ns pulses a spectrum of ~1.5 cmsup-1/supcould be recorded. Under these laser operation conditions and a gas pressure of 1000 mbar a limit of detection (3σ) of 1.5 ppmv for hydrogen sulfide (Hsub2/subS) in nitrogen was achieved using a 100 m Herriott cell and a thermoelectric cooled MCT detector for absorption measurements. Using 3 µs long pulses enabled to further extend the spectral bandwidth to 8.5 cmsup-1/sup. Based on this increased spectral coverage and employing reduced pressure conditions (50 mbar) multiple peaks of the target analyte Hsub2/subS as well as methane (CHsub4/sub) could be examined within one single pulse. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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