近日，美国国家标准与技术研究院的David A. Long及其研究团队与科罗拉多大学的Gregory B. Rieker等人合作并取得一项新进展。经过不懈努力，他们成功获得纳秒级时间分辨双梳吸收光谱 。相关研究成果已于2023年10月30日在国际知名学术期刊《自然—光子学》上发表。

该研究团队成功演示了一种全新的光学频率梳生成方法。该方法利用一对电光梳在近红外区域产生，然后在单个光学参量振荡器内以高互相干性和高效率转移到中红外区域。这些梳状光源具有高功率、互相干性和灵活的重复率，以及在中红外区域的大量分子物种的吸收特性，使得完全分辨的光谱跃迁能够在短至20纳秒的时间尺度内被记录下来。研究人员已经应用这种方法研究了超音速脉冲射流中的快速动力学过程，然而，他们也注意到这种方法在化学、量子物理、大气化学、燃烧科学以及生物学等领域具有广泛的应用潜力。

据悉，频率梳技术的出现彻底颠覆了光谱学领域，它为研究人员提供了大量精确的光学频率，以探测分子系统。尽管直接频率梳光谱技术已经取得了显著的进步，但在纳秒级时间尺度上，这些方法仍无法记录许多物理化学过程的高分辨率光谱。

附：英文原文

Title: Nanosecond time-resolved dual-comb absorption spectroscopy

Author: Long, David A., Cich, Matthew J., Mathurin, Carl, Heiniger, Adam T., Mathews, Garrett C., Frymire, Augustine, Rieker, Gregory B.

Issue&Volume: 2023-10-30

Abstract: Frequency combs have revolutionized the field of optical spectroscopy, enabling researchers to probe molecular systems with a multitude of accurate and precise optical frequencies. Although there have been tremendous strides in direct frequency comb spectroscopy, these approaches have been unable to record high-resolution spectra on the nanosecond-timescale characteristic of many physiochemical processes. Here we demonstrate a new approach to achieve optical frequency comb generation in which a pair of electro-optic combs is produced in the near-infrared regime and subsequently transferred with high mutual coherence and efficiency into the mid-infrared regime within a single optical parametric oscillator. The high power, mutual coherence and agile repetition rates of these combs, as well as the large mid-infrared absorption of many molecular species, enable fully resolved spectral transitions to be recorded in timescales as short as 20ns. We have applied this approach to study the rapid dynamics occurring within a supersonic pulsed jet; however, we note that this method is widely applicable to fields such as chemical and quantum physics, atmospheric chemistry, combustion science and biology.

DOI: 10.1038/s41566-023-01316-8

Source: https://www.nature.com/articles/s41566-023-01316-8