Mid-infrared trace detection with parts-per-quadrillion quantitation accuracy: Expanding frontiers of radiocarbon sensing

• 成果类型: Article
• 署名作者: Jiang, Jun; McCartt, A. Daniel
• 署名单位: United States Department of Energy (DOE); Lawrence Livermore National Laboratory
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9330
• DOI: 10.1073/pnas.2314441121
• 发表日期: 2024-04-09
• 关键词: rotation spectroscopy; dioxide detection; extinction-ratio; c-14; co2; oh; radicals; band

摘要

Detection sensitivity is a critical characteristic to consider during selection of spectroscopic techniques. However, high sensitivity alone is insufficient for spectroscopic measurements in spectrally congested regions. Two-color cavity ringdown spectroscopy (2C-CRDS), based on intra-cavity pump-probe detection, simultaneously achieves high detection sensitivity and selectivity. This combination enables mid-infrared detection of radiocarbon dioxide ((CO2)-C-14) molecules in room-temperature CO2 samples, with 1.4 parts-per-quadrillion (ppq, 10 15) sensitivity (average measurement precision) and 4.6-ppq quantitation accuracy (average calibrated measurement error for 21 samples from four separate trials) demonstrated on samples with C-14/C up to similar to 1.5x natural abundance (similar to 1,800 ppq). These highly reproducible measurements, which are the most sensitive and quantitatively accurate in the mid-infrared, are accomplished despite the presence of orders-of-magnitude stronger, one-photon signals from other CO2 isotopologues. This is a major achievement in laser spectroscopy. A room-temperature-operated, compact, and low-cost 2C-CRDS sensor for (CO2)-C-14 benefits a wide range of scientific fields that utilize C-14 for dating and isotope tracing, most notably atmospheric (CO2)-C-14 monitoring to track CO2 emissions from fossil fuels. The 2C-CRDS technique significantly enhances the general utility of high-resolution mid-infrared detection for analytical measurements and fundamental chemical dynamics studies.