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| Main Authors: | , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2506.17107 |
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| _version_ | 1866914307019636736 |
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| author | Dong, Jinghan Nie, Weijie Cardoso, Arthur C. Zhou, Haichen Zhang, Jingrui Rarity, John G. Clark, Alex S. |
| author_facet | Dong, Jinghan Nie, Weijie Cardoso, Arthur C. Zhou, Haichen Zhang, Jingrui Rarity, John G. Clark, Alex S. |
| contents | Nonlinear interferometry has widespread applications in sensing, spectroscopy, and imaging. However, most implementations require highly reflective mirrors and precise optical alignment, drastically reducing their versatility and usability in outdoor applications. This work is based on stimulated parametric down conversion (ST-PDC), demonstrating methane absorption spectroscopy in the mid-infrared (MIR) region by detecting near-infrared (NIR) photons using a silicon-based CMOS camera. The MIR light, used to probe methane, is diffusely backscattered from a Lambertian surface, experiencing significant transmission loss. We implement a single-mode confocal illumination and collection scheme, using a two-lens system to mode-match the interfering beams to achieve background methane detection at a distance of 4.6 meters under a 60 dB loss. Our method is also extended to real-world surfaces, such as glass, brushed metal, and a leaf, showing robust background methane sensing with various target materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_17107 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Open-Path Methane Sensing via Backscattered Light in a Nonlinear Interferometer Dong, Jinghan Nie, Weijie Cardoso, Arthur C. Zhou, Haichen Zhang, Jingrui Rarity, John G. Clark, Alex S. Optics Applied Physics Nonlinear interferometry has widespread applications in sensing, spectroscopy, and imaging. However, most implementations require highly reflective mirrors and precise optical alignment, drastically reducing their versatility and usability in outdoor applications. This work is based on stimulated parametric down conversion (ST-PDC), demonstrating methane absorption spectroscopy in the mid-infrared (MIR) region by detecting near-infrared (NIR) photons using a silicon-based CMOS camera. The MIR light, used to probe methane, is diffusely backscattered from a Lambertian surface, experiencing significant transmission loss. We implement a single-mode confocal illumination and collection scheme, using a two-lens system to mode-match the interfering beams to achieve background methane detection at a distance of 4.6 meters under a 60 dB loss. Our method is also extended to real-world surfaces, such as glass, brushed metal, and a leaf, showing robust background methane sensing with various target materials. |
| title | Open-Path Methane Sensing via Backscattered Light in a Nonlinear Interferometer |
| topic | Optics Applied Physics |
| url | https://arxiv.org/abs/2506.17107 |