A compact off-axis cavity-enhanced absorption spectroscopy system with open-path configuration is developed by using a narrow-band CW laser as light source. The open-path configuration can avoid absorption cell wall losses and sampling induced artifacts. The absolute reflectivity of the cavity mirrors is determined to be 99.8% by a simple and effective method, and an effective optical path length of 315.66 m is realized based on a 45 cm long high optical finesse open-path cavity. In order to confirm the ability of the system, a series of measurements of CO₂ concentrations are performed by targeting a CO₂ line at 5001.49 cm⁻¹. According to the time series measurements of ambient CO₂, a sensitivity is 7.819 ppm while the averaging time is 1 s, and an optimum sensitivity of 193 ppb can be achieved with an averaging time of 300 s. And two 24 h’ field continuous measurements are performed to demonstrate the stability of the reported system.

通过使用窄带连续波激光器作为光源，开发了具有开放路径配置的紧凑型离轴腔增强吸收光谱系统。开路配置可以避免吸收池壁损失和采样引起的伪像。通过一种简单有效的方法将腔镜的绝对反射率确定为99.8％，并且基于45厘米长的高光学精细开放路径腔，可实现315.66 m的有效光路长度。为了确认系统的能力，通过将CO ₂线对准5001.49 cm ^-1来进行一系列的CO ₂浓度测量。根据时间序列测量环境CO ₂，灵敏度为7.819 ppm，而平均时间为1 s，而平均时间为300 s，则可实现193 ppb的最佳灵敏度。并进行了两次24小时现场连续测量，以证明所报道系统的稳定性。