Open AccessReal-time standoff detection of nitrogen isotopes in ammonia plumes using a swept external cavity quantum cascade laser
Author(s) -
Mark C. Phillips,
Brian E. Brumfield,
S. S. Harilal
Publication year - 2018
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.43.004065
Subject(s) - quantum cascade laser , optics , isotope , cascade , plume , laser , materials science , wavelength , physics , analytical chemistry (journal) , chemistry , nuclear physics , meteorology , chromatography
A swept-wavelength external cavity quantum cascade laser is used to measure time-resolved NH 3 15 and NH 3 14 concentrations and isotope ratios in a turbulent plume source located at 10 m standoff distance. Measurements show excellent agreement with expected values of isotope ratios for samples with natural and enriched N15 abundance. Detection sensitivity of 150 ppb*m is demonstrated for a 50 ms measurement interval, improving to 10 ppb*m with 10 s averaging, with isotopic precision as good as 0.8%.