This type of sensor can also be used to monitor the combustion efficiency in terrestrial gas turbine and high-pressure combustion systems where a rugged sensor with long operating life characteristics is needed. Also it is possible to use this sensor for real-time biological measurements as the system can also be used as a Fraunhofer Line Discriminator Spectrometer for sub-angstrom remote sensing of fluorescence emission in the Fraunhofer line wavelengths. Finally, large and complex molecules that have extremely broad absorption signatures could be fully resolved with this sensor, with application to national security sensing of weapons and explosives. There are many commercial and military applications for an accurate and rugged laser absorption system capable of acting as a pressure, temperature and/or concentration sensor. The sensor could be used in both new and retrofit commercial aircraft as a control sensor for propulsion systems, in industry and environmental monitoring as sensitive gas leak sensor, as concentration mapping sensor both for local and remote sensing applications, including on mobile platforms. Furthermore, due to the wide filter tuneability, the built-in calibration and the variety of possible wideband light sources; this sensor could replace Tunable Diode Laser Absorption Spectroscopy (TDLAS) sensors in a number of applications as there is a demonstrable advantage in system cost, complexity, and operation.