URL: https://www.researchgate.net/publication/380048921/figure/fig1/AS:11431281242212261@1715376120263/Passive-differential-optical-absorption-spectroscopy-DOAS-schematic-and-its-spectral.tif
URL2: https://www.researchgate.net/figure/Passive-differential-optical-absorption-spectroscopy-DOAS-schematic-and-its-spectral_fig1_380048921
