Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
J Chem Phys. 2013 Mar 7;138(9):094201. doi: 10.1063/1.4792372.
We present a low uncertainty measurement technique for determining molecular transition frequencies. This approach is complementary to sub-Doppler saturation spectroscopies and is expected to enable new frequency measurements for a wide variety of molecular species with uncertainties at the kHz-level. The technique involves measurements of Doppler broadened lines using cavity ring-down spectroscopy whereby the probe laser is actively locked to the ring-down cavity and the spectrum frequencies are linked directly to an optical frequency comb that is referenced to an atomic frequency standard. As a demonstration we have measured the transition frequency of the (30012) ← (00001) P14e line of CO2 near 1.57 μm with a combined standard uncertainty of ~9 kHz. This technique exhibits exceptional promise for measurements of transition frequencies and pressure shifting parameters of many weak absorbers, and indicates the potential for substantially improved measurements when compared to those obtained with conventional spectroscopic methods.
我们提出了一种低不确定度测量技术，用于确定分子跃迁频率。这种方法是对亚多普勒饱和光谱学的补充，有望为各种分子种类实现新的频率测量，其不确定度达到 kHz 级别。该技术涉及使用腔衰荡光谱法测量多普勒展宽线，其中探测激光被主动锁定到腔衰荡腔，并且光谱频率直接与光学频率梳相关联，该光学频率梳参考原子频率标准。作为演示，我们已经测量了近 1.57μm 处 CO2 的 (30012) ← (00001) P14e 线的跃迁频率，其组合标准不确定度约为 9 kHz。该技术在测量许多弱吸收体的跃迁频率和压力移动参数方面具有特殊的应用前景，并且与传统光谱方法相比，有望实现显著改进的测量。
