Chen Jie, Zhao Xin, Yao Zijun, Li Ting, Li Qian, Xie Shuguo, Liu Jiansheng, Zheng Zheng
Opt Express. 2019 Apr 15;27(8):11406-11412. doi: 10.1364/OE.27.011406.
Dual-comb spectroscopy has been developed into a high-precision technique that is capable of sensing many important species of samples, such as methane. Recent studies on single-cavity, dual-comb light sources further reduce the system complexity of such schemes. In contrast to the previous demonstrations around the lasing spectrum, this work significantly expands the spectral coverage of a dual-comb spectroscopy setup using one free-running laser to a region far beyond the laser's emission wavelengths. Nonlinear wavelength conversion based on soliton self-frequency shift is adopted to convert and tune the wavelengths of both dual-comb pulses to ~1650nm. It is shown that this process has introduced little additional intensity noise. The 2ν absorption band of methane from 1647 nm to 1663nm is measured with very good agreement with HITRAN, and the standard deviation of the residual is < ~0.006 after averaging ~1.96 seconds of data. Our results further elucidate the potential of dual-comb spectroscopy using one laser, and could pave the way for the development of low-cost, power-efficient, and compact dual-comb instrument targeting more spectral regions.
双梳状光谱已发展成为一种高精度技术，能够检测许多重要的样品种类，如甲烷。近期对单腔双梳状光源的研究进一步降低了此类方案的系统复杂性。与之前围绕激光光谱的演示不同，这项工作显著扩展了双梳状光谱装置的光谱覆盖范围，利用一台自由运转激光器将其扩展到远超出激光发射波长的区域。采用基于孤子自频移的非线性波长转换，将双梳状脉冲的波长转换并调谐至1650nm。结果表明，该过程几乎没有引入额外的强度噪声。测量了甲烷在1647nm至1663nm的2ν吸收带，与HITRAN的结果吻合良好，在对约1.96秒的数据进行平均后，残余的标准偏差<0.006。我们的结果进一步阐明了使用一台激光器的双梳状光谱的潜力，并可为开发针对更多光谱区域的低成本、高能效且紧凑的双梳状仪器铺平道路。
