Oxygen A-band absorption spectroscopy with solar photon counting and lithium niobate nanophotonic circuits

• Published in: Frontiers in remote sensing Vol. 3
• Main Authors: Zhang, Jiuyi, Sua, Yong Meng, Hu, Yongxiang, Ramanathan, Jeevanandha, Huang, Yu-Ping
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 18-11-2022
• Subjects: oxygen A-band; oxygen absorption spectrum; photonic integrated circuits; remote sensing; solar photon counting; thin film lithium niobate
• ISSN: 2673-6187; 2673-6187
• DOI: 10.3389/frsen.2022.1064244

Oxygen A-band measurements can provide important information about cloud top height, cloud physical and optical thickness, and surface atmospheric pressure. So far, O
2
A-band measurements are typically made with spectrometers at a spectral resolution of 40 p.m. (such as in the OCO-2 satellite) or a coarser resolution. This paper reports a new CubeSat measurement concept with higher spectral resolution over the O
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A-band using integrated photonic circuits and solar photon counting techniques. An integrated Micro-ring filter (MRR) chip with 10 p.m. resonant linewidth with an extinction ratio of 25 dB or higher is designed, fabricated, and used for precise measurements of the atmospheric oxygen A-band absorption line-shapes around 770 nm. With solar-photon counting and using a narrow-band filter made of an integrated, fast-swept MRR on lithium niobate on insulator (LNOI), we have demonstrated a high-resolution measurement of the O
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A-band absorption spectrum, exhibiting good agreement with the HITRAN database.