Yu Haoyang, Zhou Qian, Li Xinghui, Wang Xiaohao, Wang Xilin, Ni Kai
Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environments, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Sensors (Basel). 2021 Jan 29;21(3):903. doi: 10.3390/s21030903.
Dual-comb spectroscopy has been an infusive spectroscopic tool for gas detection due to its high resolution, high sensitivity, and fast acquisition speed over a broad spectral range without any mechanical scanning components. However, the complexity and cost of high-performance dual-comb spectroscopy are still high for field-deployed applications. To solve this problem, we propose a simple frequency domain post-processing method by extracting the accurate position of a specific absorption line frame by frame. After aligning real-time spectra and averaging for one second, the absorbance spectrum of HCN gas in the near-infrared is obtained over 1.1 THz spectral range. By using this method, the standard deviation of residual error is only ~0.002, showing great agreement with the conventional correction method. In addition, the spectral resolution is improved from 13.4 GHz to 4.3 GHz compared to direct spectrum averaging. Our method does not require a specially designed common-mode suppression comb, rigorous frequency control system, or complicated computational algorithm, providing a cost-effective scheme for field-deployed Doppler-limited spectroscopy applications.
双梳状光谱技术因其具有高分辨率、高灵敏度以及在宽光谱范围内无需任何机械扫描部件即可快速采集光谱的特性，一直是一种广泛应用于气体检测的光谱工具。然而，对于现场部署应用而言，高性能双梳状光谱技术的复杂性和成本仍然很高。为了解决这个问题，我们提出了一种简单的频域后处理方法，即逐帧提取特定吸收线的精确位置。在对实时光谱进行对齐并平均一秒钟后，在1.1太赫兹光谱范围内获得了近红外波段HCN气体的吸收光谱。通过使用这种方法，残余误差的标准偏差仅约为0.002，与传统校正方法显示出高度一致性。此外，与直接光谱平均相比，光谱分辨率从13.4吉赫兹提高到了4.3吉赫兹。我们的方法不需要专门设计的共模抑制梳状滤波器、严格的频率控制系统或复杂的计算算法，为现场部署的多普勒极限光谱应用提供了一种经济高效的方案。
