The Aircraft Laser Infrared Absorption Spectrometer (ALIAS) instrument is a high-resolution (0.0003 cm−1) scanning tunable-diode-laser spectrometer designed, tested, and flown more than 30 times on the National Aeronautics and Space Administration’s high-altitude ER-2 aircraft in the Airborne Arctic Stratospheric Expedition of 1991–1992. Using long-path infrared laser absorption spectroscopy to detect optical absorptions as small as 10−5, ALIAS provides fast, continuous in-situ measurements of key atmospheric gases, with gas detection sensitivities of tens of parts in 1012. With four lasers and detectors in a single liquid-nitrogen Dewar, simultaneous measurements of HCl, NO2, HNO3, CH4, and NO2 are made using laser sources at 3.4–8 μm, injected into a 1-m-long, 80-pass Herriott cell.
© 1994 Optical Society of America
Original Manuscript: January 7, 1993
Revised Manuscript: July 20, 1993
Published: January 20, 1994
C. R. Webster, R. D. May, C. A. Trimble, R. G. Chave, and J. Kendall, "Aircraft (ER-2) laser infrared absorption spectrometer (ALIAS) for in-situ stratospheric measurements of HCl, N2O, CH4, NO2, and HNO3," Appl. Opt. 33, 454-472 (1994)