Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser
Cavity ringdown spectroscopy (CRDS), relying on measuring the decay time of photons inside a high-finesse optical cavity, offers an important analytical tool for chemistry, physics, environmental science, and biology. Through the reflection of a slight amount of phase-coherent light back to the lase...
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| Format: | Article |
| Language: | English |
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Institue of Optics and Electronics, Chinese Academy of Sciences
2024-11-01
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| Series: | Opto-Electronic Advances |
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| Online Access: | https://www.oejournal.org/article/doi/10.29026/oea.2024.240077 |
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| author | Qinxue Nie Yibo Peng Qiheng Chen Ningwu Liu Zhen Wang Cheng Wang Wei Ren |
| author_facet | Qinxue Nie Yibo Peng Qiheng Chen Ningwu Liu Zhen Wang Cheng Wang Wei Ren |
| author_sort | Qinxue Nie |
| collection | DOAJ |
| description | Cavity ringdown spectroscopy (CRDS), relying on measuring the decay time of photons inside a high-finesse optical cavity, offers an important analytical tool for chemistry, physics, environmental science, and biology. Through the reflection of a slight amount of phase-coherent light back to the laser source, the resonant optical feedback approach effectively couples the laser beam into the optical cavity and achieves a high signal-to-noise ratio. However, the need for active phase-locking mechanisms complicates the spectroscopic system, limiting its primarily laboratory-based use. Here, we report how passive optical feedback can be implemented in a quantum cascade laser (QCL) based CRDS system to address this issue. Without using any phase-locking loops, we reflect a moderate amount of light (–18.2 dB) to a continuous-wave QCL simply using a fixed flat mirror, narrowing the QCL linewidth from 1.2 MHz to 170 kHz and significantly increasing the laser-cavity coupling efficiency. To validate the method’s feasibility and effectiveness, we measured the absorption line (P(18e), 2207.62 cm−1) of N2O in a Fabry–Perot cavity with a high finesse of ~52000 and an inter-mirror distance of 33 cm. This agile approach paves the way for revolutionizing existing analytical tools by offering compact and high-fidelity mid-infrared CRDS systems. |
| format | Article |
| id | doaj-art-420ffe6e2fff4d92b14e767c98a6c6e6 |
| institution | Kabale University |
| issn | 2096-4579 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Institue of Optics and Electronics, Chinese Academy of Sciences |
| record_format | Article |
| series | Opto-Electronic Advances |
| spelling | doaj-art-420ffe6e2fff4d92b14e767c98a6c6e62025-01-11T07:03:41ZengInstitue of Optics and Electronics, Chinese Academy of SciencesOpto-Electronic Advances2096-45792024-11-017111810.29026/oea.2024.240077OEA-2024-0077RenweiAgile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laserQinxue Nie0Yibo Peng1Qiheng Chen2Ningwu Liu3Zhen Wang4Cheng Wang5Wei Ren6Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR 999077, ChinaSchool of Information Science and Technology, ShanghaiTech University, Shanghai 201210, ChinaDepartment of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR 999077, ChinaDepartment of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR 999077, ChinaDepartment of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR 999077, ChinaSchool of Information Science and Technology, ShanghaiTech University, Shanghai 201210, ChinaDepartment of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR 999077, ChinaCavity ringdown spectroscopy (CRDS), relying on measuring the decay time of photons inside a high-finesse optical cavity, offers an important analytical tool for chemistry, physics, environmental science, and biology. Through the reflection of a slight amount of phase-coherent light back to the laser source, the resonant optical feedback approach effectively couples the laser beam into the optical cavity and achieves a high signal-to-noise ratio. However, the need for active phase-locking mechanisms complicates the spectroscopic system, limiting its primarily laboratory-based use. Here, we report how passive optical feedback can be implemented in a quantum cascade laser (QCL) based CRDS system to address this issue. Without using any phase-locking loops, we reflect a moderate amount of light (–18.2 dB) to a continuous-wave QCL simply using a fixed flat mirror, narrowing the QCL linewidth from 1.2 MHz to 170 kHz and significantly increasing the laser-cavity coupling efficiency. To validate the method’s feasibility and effectiveness, we measured the absorption line (P(18e), 2207.62 cm−1) of N2O in a Fabry–Perot cavity with a high finesse of ~52000 and an inter-mirror distance of 33 cm. This agile approach paves the way for revolutionizing existing analytical tools by offering compact and high-fidelity mid-infrared CRDS systems.https://www.oejournal.org/article/doi/10.29026/oea.2024.240077cavity ringdown spectroscopyoptical feedbackquantum cascade lasergas sensing |
| spellingShingle | Qinxue Nie Yibo Peng Qiheng Chen Ningwu Liu Zhen Wang Cheng Wang Wei Ren Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser Opto-Electronic Advances cavity ringdown spectroscopy optical feedback quantum cascade laser gas sensing |
| title | Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser |
| title_full | Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser |
| title_fullStr | Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser |
| title_full_unstemmed | Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser |
| title_short | Agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser |
| title_sort | agile cavity ringdown spectroscopy enabled by moderate optical feedback to a quantum cascade laser |
| topic | cavity ringdown spectroscopy optical feedback quantum cascade laser gas sensing |
| url | https://www.oejournal.org/article/doi/10.29026/oea.2024.240077 |
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