We present an ultrasensitive absorption spectrometer based on a 30 Hz/s stability, sub-kHz line width laser source coupled to a high-stability cavity-ring-down-spectroscopy setup. It provides direct and precise measurements of the isotopic ratios δ¹⁷O and δ¹⁸O in CO₂. We demonstrate the first optical absorption measurements of ¹⁷O anomalies in CO₂ with a precision better than 10 ppm, matching the requirements for paleo-environmental applications. This illustrates how optical absorption methods have become a competitive alternative to state-of-the-art isotopic ratio mass spectrometry techniques.

中文翻译：

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在CO同位素丰度比的直接，精确测量₂利用分子吸收光谱法：应用于Δ ¹⁷ ö

我们提出了一种基于30 Hz / s稳定性，亚kHz线宽激光源和高稳定性腔衰荡光谱仪的超灵敏吸收光谱仪。它提供了同位素比率δ的直接和精确的测量¹⁷ O和δ ¹⁸在COÒ ₂。我们展示了CO ₂中¹⁷ O异常的首次光吸收测量，其精度优于10 ppm，符合古环境应用的要求。这说明了光吸收方法如何成为最先进的同位素比率质谱技术的竞争替代品。