Roy, AnirbanAnirbanRoyUpadhyay, AbhishekAbhishekUpadhyayLal Chakraborty, ArupArupLal Chakraborty2025-08-312025-08-312016-01-01[9781943580224]10.1364/PHOTONICS.2016.W4G.22-s2.0-85165760801https://repository.iitgn.ac.in/handle/IITG2025/27178We report the first calibration-free measurements of atmospheric CO<inf>2</inf> in the Ahmedabad-Gandhinagar area using a portable tunable diode laser spectroscopy system. Second harmonic wavelength modulation spectroscopy is implemented on a 1 mW, 2004 nm VCSEL.falseConference Paper21622701201600