调制衰荡梳干涉测量技术：解锁复杂分子检测新高度，实现多物种超灵敏定量分析

为解决中红外频率梳光谱技术中梳齿 - 腔增强受强吸收限制的问题，研究人员开展调制衰荡梳干涉测量技术研究。结果显示该技术提升了精细度和光谱覆盖范围，能超灵敏定量多种分子，对复杂分子检测意义重大，值得一读。

　　

摘要

与健康相关的气体样本^{<a href="#ref-CR1" id="ref-link-section-d22773857e325" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Thorpe, M. J., Balslev-Clausen, D., Kirchner, M. S. & Ye, J. Cavity-enhanced optical frequency comb spectroscopy: application to human breath analysis. Opt. Express 16, 2387–2397 (2008).">1</a>,<a href="#ref-CR2" id="ref-link-section-d22773857e325_1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Liang, Q. et al. Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnostics. Proc. Natl Acad. Sci. 118, e2105063118 (2021).">2</a>,<a href="/articles/s41586-024-08534-2#ref-CR3" id="ref-link-section-d22773857e328" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Liang, Q. et al. Breath analysis by ultra-sensitive broadband laser spectroscopy detects SARS-CoV-2 infection. J. Breath Res. 17, 036001 (2023).">3</a>}以及与环境相关的气体样本^{<a href="#ref-CR4" id="ref-link-section-d22773857e332" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Rieker, G. B. et al. Frequency-comb-based remote sensing of greenhouse gases over kilometer air paths. Optica 1, 290–298 (2014).">4</a>,<a href="#ref-CR5" id="ref-link-section-d22773857e332_1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Herman, D. I. et al. Precise multispecies agricultural gas flux determined using broadband open-path dual-comb spectroscopy. Sci. Adv. 7, eabe9765 (2021).">5</a>,<a href="/articles/s41586-024-08534-2#ref-CR6" id="ref-link-section-d22773857e335" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 6" title="Giorgetta, F. R. et al. Open-path dual-comb spectroscopy for multispecies trace gas detection in the 4.5–5 μm spectral region. Laser Photonics Rev. 15, 2000583 (2021).">6</a>}通常包含多种分子种类，其浓度动态范围极大。具有高精细度腔增强的中红外频率梳光谱技术实现了目前最为灵敏的多物种痕量气体检测^{<a href="/articles/s41586-024-08534-2#ref-CR2" id="ref-link-section-d22773857e339" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" title="Liang, Q. et al. Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnostics. Proc. Natl Acad. Sci. 118, e2105063118 (2021).">2</a>,<a href="#ref-CR7" id="ref-link-section-d22773857e342" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Bui, T. Q. et al. Spectral analyses of trans- and cis-DOCO transients via comb spectroscopy. Mol. Phys. 116, 3710–3717 (2018).">7</a>,<a href="#ref-CR8" id="ref-link-section-d22773857e342_1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Changala, P. B., Spaun, B., Patterson, D., Doyle, J. M. & Ye, J. Sensitivity and resolution in frequency comb spectroscopy of buffer gas cooled polyatomic molecules. Appl. Phys. B 122, 292 (2016).">8</a>,<a href="#ref-CR9" id="ref-link-section-d22773857e342_2" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Spaun, B. et al. Continuous probing of cold complex molecules with infrared frequency comb spectroscopy. Nature 533, 517–520 (2016).">9</a>,<a href="#ref-CR10" id="ref-link-section-d22773857e342_3" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Foltynowicz, A., Maslowski, P., Fleisher, A. J., Bjork, B. J. & Ye, J. Cavity-enhanced optical frequency comb spectroscopy in the mid-infrared application to trace detection of hydrogen peroxide. Appl. Phys. B 110, 163–175 (2013).">10</a>,<a href="#ref-CR11" id="ref-link-section-d22773857e342_4" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Changala, P. B., Weichman, M. L., Lee, K. F., Fermann, M. E. & Ye, J. Rovibrational quantum state resolution of the C60 fullerene. Science 363, 49–54 (2019).">11</a>,<a href="#ref-CR12" id="ref-link-section-d22773857e342_5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Bjork, B. J. et al. Direct frequency comb measurement of OD + CO → DOCO kinetics. Science 354, 444–448 (2016).">12</a>,<a href="/articles/s41586-024-08534-2#ref-CR13" id="ref-link-section-d22773857e345" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 13" title="Bui, T. Q. et al. Direct measurements of DOCO isomers in the kinetics of OD + CO. Sci. Adv. 4, eaao4777 (2018).">13</a>}。然而，该技术的稳定性能在很大程度上依赖于在宽光谱范围内实现吸收光程长度的增强，而当存在强吸收化合物时，梳齿 - 腔频率失配会严重限制这一增强效果。在此，我们介绍调制衰荡梳干涉测量技术，该技术解决了梳齿 - 腔增强对腔内强吸收或色散的敏感性问题。该技术通过测量经长度调制腔传输的大量平行梳齿线所携带的衰荡动力学过程来实现，利用了场动力学的周期性以及迈克尔逊干涉仪引入的多普勒频移。作为演示，我们在中红外区域对色散性强的人体呼出气体样本和环境空气进行测量，精细度提高到 23000，光谱覆盖范围达到 1010 cm^?1。这种精细度与光谱覆盖范围的乘积比之前所有的演示结果都高出几个数量级^{<a href="/articles/s41586-024-08534-2#ref-CR2" id="ref-link-section-d22773857e351" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" title="Liang, Q. et al. Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnostics. Proc. Natl Acad. Sci. 118, e2105063118 (2021).">2</a>,<a href="#ref-CR7" id="ref-link-section-d22773857e354" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Bui, T. Q. et al. Spectral analyses of trans- and cis-DOCO transients via comb spectroscopy. Mol. Phys. 116, 3710–3717 (2018).">7</a>,<a href="#ref-CR8" id="ref-link-section-d22773857e354_1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Changala, P. B., Spaun, B., Patterson, D., Doyle, J. M. & Ye, J. Sensitivity and resolution in frequency comb spectroscopy of buffer gas cooled polyatomic molecules. Appl. Phys. B 122, 292 (2016).">8</a>,<a href="#ref-CR9" id="ref-link-section-d22773857e354_2" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Spaun, B. et al. Continuous probing of cold complex molecules with infrared frequency comb spectroscopy. Nature 533, 517–520 (2016).">9</a>,<a href="#ref-CR10" id="ref-link-section-d22773857e354_3" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Foltynowicz, A., Maslowski, P., Fleisher, A. J., Bjork, B. J. & Ye, J. Cavity-enhanced optical frequency comb spectroscopy in the mid-infrared application to trace detection of hydrogen peroxide. Appl. Phys. B 110, 163–175 (2013).">10</a>,<a href="#ref-CR11" id="ref-link-section-d22773857e354_4" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Changala, P. B., Weichman, M. L., Lee, K. F., Fermann, M. E. & Ye, J. Rovibrational quantum state resolution of the C60 fullerene. Science 363, 49–54 (2019).">11</a>,<a href="#ref-CR12" id="ref-link-section-d22773857e354_5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Bjork, B. J. et al. Direct frequency comb measurement of OD + CO → DOCO kinetics. Science 354, 444–448 (2016).">12</a>,<a href="#ref-CR13" id="ref-link-section-d22773857e354_6" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Bui, T. Q. et al. Direct measurements of DOCO isomers in the kinetics of OD + CO. Sci. Adv. 4, eaao4777 (2018).">13</a>,<a href="#ref-CR14" id="ref-link-section-d22773857e354_7" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Fleisher, A. J. et al. Mid-infrared time-resolved frequency comb spectroscopy of transient free radicals. J. Phys. Chem. Lett. 5, 2241–2246 (2014).">14</a>,<a href="#ref-CR15" id="ref-link-section-d22773857e354_8" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Lu, C., Morville, J., Rutkowski, L., Vieira, F. S. & Foltynowicz, A. Cavity-enhanced frequency comb vernier spectroscopy. Photonics 9, 222 (2022).">15</a>,<a href="#ref-CR16" id="ref-link-section-d22773857e354_9" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Sulzer, P. et al. Cavity-enhanced field-resolved spectroscopy. Nat. Photonics 16, 692–697 (2022).">16</a>,<a href="#ref-CR17" id="ref-link-section-d22773857e354_10" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Khodabakhsh, A. et al. Fourier transform and Vernier spectroscopy using an optical frequency comb at 3–5.4 μm. Opt. Lett. 41, 2541–2544 (2016).">17</a>,<a href="#ref-CR18" id="ref-link-section-d22773857e354_11" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Sterczewski, L. A. et al. Cavity-enhanced Vernier spectroscopy with a chip-scale mid-infrared frequency comb. ACS Photonics 9, 994–1001 (2022).">18</a>,<a href="#ref-CR19" id="ref-link-section-d22773857e354_12" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Haakestad, M. W., Lamour, T. P., Leindecker, N., Marandi, A. & Vodopyanov, K. L. Intracavity trace molecular detection with a broadband mid-IR frequency comb source. J. Opt. Soc. Am. B 30, 631–640 (2013).">19</a>,<a href="/articles/s41586-024-08534-2#ref-CR20" id="ref-link-section-d22773857e357" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 20" title="Markus, C. R. et al. Cavity-enhanced dual-comb spectroscopy in the molecular fingerprint region using free-running quantum cascade lasers. J. Opt. Soc. Am. B 41, E56–E64 (2024).">20</a>}，使我们能够同时以高于万亿分之一的灵敏度对 20 种不同的分子种类进行定量分析，这些分子的浓度变化范围可达 7 个数量级。这项技术为复杂和动态的分子组成分析开启了下一代传感性能，在精细度和光谱覆盖范围方面都具有可扩展的改进空间。