Kenji Kuriyama et al. set out to measure atmospheric CO2 concentrations using the Differential Optical Absorption Spectroscopy (DOAS) method in the near-infrared spectral region in order to contribute to the global effort to reduce greenhouse gas emissions. The infrared and near-infrared (NIR) absorption of CO2, CH4 and other trace molecular species is the main cause of the global warming effect. Various species located in the lower troposphere can be effectively monitored using DOAS in the visible spectral range. The DOAS method measures air pollutants by measuring the absorption and scattering of light over a light path of a few kilometers. Before obtaining atmospheric-scale measurements, Kenju Kuriyama et al. produced and measured in laboratory tests that used a tungsten lamp and a CO2 sample cell. The CO2 absorption measurement was conducted by passing a 100 W light beam from a tungsten lamp through a 30 mm diameter and 1000 mm long quartz tube containing CO2 gas at a pressure of 1 atm. The light was detected by an InGaAs NIR detector in the re wavelength...