Tunable diode laser spectrometers, or TDL spectrometers for short, are gas analyzers that are used for measuring the concentration of specific species within a gas mixture, using laser absorption spectrometry. In a TDL spectrometer, a laser beam, tuned to identify a particular gas species, passes through the gas to a detector. The presence of this gas in the stream causes light absorption and reduced signal intensity. The light that arrives at the detector of the TDL spectrometer is captured by a photodiode and analyzed to quantify the gas concentration.