METHOD AND APPARATUS FOR THE DETECTION OF GAS

摘要

The invention provides a gas detection system and method for detecting a target gas, in which a transmitter unit (26) directs a primary beam (32) of coherent radiation at a wavelength absorbed by the target gas along a primary optical path, and an optical device (44) directs a secondary beam (46) of coherent radiation along a further optical path. A receiver unit (28) receives the primary and the secondary beams of coherent radiation, and an optical beam combiner (52) combines the two beams of radiation to form a combined beam. The primary beam and the secondary beam are controlled to generate interference in the combined beam, and a measuring detector (35) of the receiver unit is arranged to detect interference fringes generated by the interference.