Trabold Barbara M, Hupfer Robert J R, Abdolvand Amir, St J Russell Philip
Opt Lett. 2017 Sep 1;42(17):3283-3286. doi: 10.1364/OL.42.003283.
We report the use of coherent anti-Stokes Raman spectroscopy (CARS) in gas-filled hollow-core photonic crystal fiber (HC-PCF) for trace gas detection. The long optical path-lengths yield a 60 dB increase in the signal level compared with free-space arrangements. This enables a relatively weak supercontinuum (SC) to be used as Stokes seed, along with a ns pump pulse, paving the way for broadband (>4000 cm) single-shot CARS with an unprecedented resolution of ∼100 MHz. A kagomé-style HC-PCF provides broadband guidance, and, by operating close to the pressure-tunable zero dispersion wavelength, we can ensure simultaneous phase-matching of all gas species. We demonstrate simultaneous measurement of the concentrations of multiple trace gases in a gas sample introduced into the core of the HC-PCF.
我们报道了在充有气体的空心光子晶体光纤（HC-PCF）中使用相干反斯托克斯拉曼光谱（CARS）进行痕量气体检测。与自由空间配置相比，长光程使信号电平提高了60 dB。这使得相对较弱的超连续谱（SC）能够与纳秒泵浦脉冲一起用作斯托克斯种子，为宽带（>4000 cm）单次CARS铺平了道路，其具有前所未有的约100 MHz分辨率。一种 kagomé 型 HC-PCF 提供宽带导光，并且通过在接近压力可调零色散波长下操作，我们可以确保所有气体种类的同时相位匹配。我们展示了对引入到HC-PCF纤芯中的气体样品中多种痕量气体浓度的同时测量。
