High-Sensitivity Raman Gas Probe for In Situ Multi-Component Gas Detection

Abstract

Multiple reflection has been proven to be an effective method to enhance the gas detection sensitivity of Raman spectroscopy, while Raman gas probes based on the multiple reflection principle have been rarely reported on. In this paper, a multi-reflection, cavity enhanced Raman spectroscopy (CERS) probe was developed and used for in situ multi-component gas detection. Owing to signal transmission through optical fibers and the miniaturization of multi-reflection cavity, the CERS probe exhibited the advantages of in situ detection and higher detection sensitivity. Compared with the conventional, backscattering Raman layout, the CERS probe showed a better performance for the detection of weak signals with a relatively lower background. According to the 3σ criteria, the detection limits of this CERS probe for methane, hydrogen, carbon dioxide and water vapor are calculated to be 44.5 ppm, 192.9 ppm, 317.5 ppm and 0.67%, respectively. The results presented the development of this CERS probe as having great potential to provide a new method for industrial, multi-component online gas detection.

Depolarization Ratio of the ν1 Raman Band of Pure CH4 and Perturbed by N2 and CO2

“…Despite the recent advances in the field of amplification of the Raman signal [ 1 , 2 , 3 , 4 ], the experimental setup based on the single-pass excitation scheme was used to obtain reliable data in this study. Figure 1 and Table 1 present the scheme and the main characteristics of the setup, respectively.…”

“…The recent appearance of high-sensitivity photodetectors and powerful small-size lasers provides an opportunity to amplify the useful signal and decrease the limit of detection (LOD) of the method. Other amplification methods include the multi-pass optical cells [ 1 , 2 , 3 , 4 ] or hollow-core fiber [ 5 , 6 , 7 , 8 ]. However, compression of the analyzed medium to a higher pressure is the most effective and easy to implement signal amplification approach [ 9 , 10 ].…”

Pneumatically Tunable Droplet Microlaser

“…The humidity sensing performance is better than that of the recent cavity-enhanced Raman spectroscopic technique. [33] The quick and large spectral response of micro-IL to air convections and humidity enables spectroscopic detection of flow turbulence in an open environment. When dry N 2 gas is directed toward a micro-IL droplet set under atmosphere with the flow direction parallel to the substrate, the lasing peaks of micro-IL show a blueshift (0.11 nm) and then stabilize with 𝜎 of 0.012 nm (Figure 3b).…”

Aerogel-Lined Capillaries for Raman Signal Gain of Aqueous Mixtures

“…Consequently, the matter in the probe volume is effectively excited multiple times. Configurations such as this have also proven to be applicable outside of research labs in field experiments or in industrial environments for liquid and gaseous matter [10][11][12][13][14][15][16][17]. Alternative confinement strategies utilise channels, which simultaneously serve as fluid and light guides.…”