Luo Pei-Ling, Horng Er-Chien, Guan Yu-Chan
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
Phys Chem Chem Phys. 2019 Aug 21;21(33):18400-18405. doi: 10.1039/c9cp03090e.
Molecular spectroscopy in the mid-infrared spectral range is expected to present fingerprints of chemical species that provide a unique identification with adequate sensitivity. Dual-comb spectroscopy, a promising successor to conventional Fourier-transform spectroscopy, enables rapid molecular fingerprinting with high-resolution and high-precision. Here, we report gas-phase transmittance and dispersion spectra by employing a rapidly tunable dual-comb spectrometer based on electro-optic frequency combs near 3 μm. The tunable spectral range >550 cm-1 and adjustable optical resolutions from a few hundred MHz to a few GHz were demonstrated. With the capabilities of wavelength agility and easily adjustable comb-mode spacing, the spectra of nitrous oxide and its isotopes were measured with Doppler-limited resolution. Furthermore, the N2-broadened spectra of acetylene were recorded to derive the collisional broadening coefficient. Fast acquisitions with adequate spectral resolution were also achieved within sub-microseconds. Both precision spectral metrology and fast molecular sampling could be implemented by employing the high-flexible dual-comb spectrometer.
中红外光谱范围内的分子光谱有望呈现化学物质的指纹图谱，这些指纹图谱能以足够的灵敏度提供独特的识别。双梳光谱作为传统傅里叶变换光谱的一种有前景的后继技术，能够实现具有高分辨率和高精度的快速分子指纹识别。在此，我们报告了通过使用基于3μm附近电光频率梳的快速可调谐双梳光谱仪获得的气相透过率和色散光谱。展示了大于550 cm-1的可调光谱范围以及从几百兆赫兹到几吉赫兹的可调光学分辨率。凭借波长捷变能力和易于调节的梳状模式间距，以多普勒极限分辨率测量了一氧化二氮及其同位素的光谱。此外，记录了乙炔的N2加宽光谱以推导碰撞加宽系数。在亚微秒内也实现了具有足够光谱分辨率的快速采集。通过采用高灵活性的双梳光谱仪，可以实现精密光谱计量和快速分子采样。
