CO2 Raman scattering measurements in seawater for marine lidar

Real-time measurement of CO
2
Raman signals can aid in determining the CO
2
concentration dissolved in the sea. We are developing a Raman lidar that can be installed into a drone for CO
2
monitoring in seawater. In this report, we present results of measuring CO
2
Raman signals dissolved in pure water and seawater using an Nd:YAG laser at a wavelength of 355 nm by using spectrometer and ICCD camera as basic experiments. We were able to detect CO
2
Raman signal could be detected up to 80 ppm when dissolved in pure water and 120 ppm when dissolved in seawater and found a correlation between CO
2
gas concentration and signal intensity. The measurement results suggest that both the intensity of Raman scattering changes linearly with respect to CO2 gas concentration from 80ppm to 1240ppm. We design the lidar configuration by considering this results of the fundamental experiment.