Background-free methods have potentially superior detection sensitivity because of their ability to take advantage of the full laser power; they are therefore attractive to spectroscopists. We implement background-free Fourier transform spectroscopy based on coherent suppression of the background using an interferometer, whereby the central peak of the interferogram is suppressed without losing molecular absorption signatures. This results in the appearance of peaks rather than dips in the measured spectrum. The technique can be used with a variety of broadband spectroscopies and features advantages such as a reduction in the required detector dynamic range, the capability to perform quantitative measurements, and strongly enhanced sensitivity down to the quantum limit. We validated our method experimentally by performing mid-infrared dual-comb spectroscopy with a mixture of multiple molecular species over a broad wavelength range of 3–5 μm.

中文翻译：

---

基于带符号反转波形的干涉抑制的无背景宽带吸收光谱

无背景方法具有利用全部激光功率的能力，因此具有潜在的优越的检测灵敏度。因此，它们对光谱学家具有吸引力。我们使用干涉仪基于背景的相干抑制，实现了无背景傅立叶变换光谱技术，从而在不损失分子吸收特征的情况下，抑制了干涉图的中心峰。这导致在测量的频谱中出现峰而不是谷。该技术可与多种宽带光谱仪一起使用，并具有以下优点：减少所需的探测器动态范围，执行定量测量的能力以及大大增强的灵敏度（直至量子极限）。