Tunable diode laser absorption spectroscopy (TDLAS, sometimes referred to as TDLS, TLS or TLAS ) is a technique for measuring the concentration of certain species such as methane, water vapor and many more, in a gaseous mixture using tunable diode lasers and laser. Tunable diode laser absorption spectroscopy (TDLAS, sometimes referred to as TDLS, TLS or TLAS ) is a technique for measuring the concentration of certain species such as methane, water vapor and many more, in a gaseous mixture using tunable diode lasers and laser. Tunable diode laser absorption spectroscopy (TDLAS, sometimes referred to as TDLS, TLS or TLAS ) is a technique for measuring the concentration of certain species such as methane, water vapor and many more, in a gaseous mixture using tunable diode lasers and laser absorption spectrometry. The. Tunable diode laser spectrometers (TDLS) allow for real-time gas analysis to increase efficiency, safety, throughput, quality, and environmental compliance. It is a proven technology free of interferences from other sample stream components. It is widely used in industries such as natural gas, petrochemicals, refining, and environmental monitoring, where accurate, real-time gas. Tunable Diode Laser Absorption Spectroscopy (TDLAS) has emerged as a versatile and reliable diagnostic tool for measuring temperature, pressure, gas composition, and velocity in power genera-tion and propulsion systems. TDLAS measures the wavelength-dependent absorption of light through a gas medium.