Raman spectroscopy measurement of CH4 gas and CH4 dissolved in water for laser remote sensing in water

We examined the applicability of Raman spectroscopy as a laser remote sensing tool for monitoring CH 4 in water. The Raman technique has already been used successfully for measurements of CO 2 gas in water. In this paper, considering the spectral transmittance of water, third harmonics of Q-switched Nd:YAG laser at 355 nm (UV region) was used for detection of CH 4 Raman signals. The Raman signal at 2892 cm -1 from CH 4 dissolved in water was detected at a tail of water Raman signal.