Landsberg J, Romanini D, Kerstel E
Opt Lett. 2014 Apr 1;39(7):1795-8. doi: 10.1364/OL.39.001795.
So far, cavity-enhanced absorption spectroscopy (CEAS) has been based on optical cavities with a high finesse F that, however, has been limited by mirror reflectivity and by cavity transmission considerations to a few times 10,000. Here, we demonstrate a compact near-infrared optical-feedback CEAS instrument for water vapor isotope ratio measurements, with F>140,000. We show that this very high finesse can be effectively exploited to improve the detection sensitivity to the full extent predicted by the increased effective path length to reach a noise equivalent absorption sensitivity of 5.7×10(-11) cm(-1) Hz(-1/2) for a full spectrum registration (including possible effects of interference fringes and fit model inadequacies).
到目前为止，腔增强吸收光谱法（CEAS）一直基于具有高精细度F的光学腔，然而，由于镜面反射率和腔传输方面的考虑，F被限制在几万倍。在此，我们展示了一种用于水汽同位素比测量的紧凑型近红外光反馈CEAS仪器，其精细度F>140,000。我们表明，这种非常高的精细度可以得到有效利用，以将检测灵敏度提高到由有效光程增加所预测的最大程度，从而在全光谱记录（包括干涉条纹和拟合模型不足的可能影响）下达到5.7×10(-11) cm(-1) Hz(-1/2)的噪声等效吸收灵敏度。
