@article { ISI:000088833600033,
	title = {Effective utilization of quantum-cascade distributed-feedback lasers in absorption spectroscopy},
	journal = {APPLIED OPTICS},
	volume = {39},
	number = {24},
	year = {2000},
	month = {AUG 20},
	pages = {4425-4430},
	publisher = {OPTICAL SOC AMER},
	type = {Article},
	address = {2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA},
	abstract = {A variable duty cycle quasi-cw frequency scanning technique was applied to reduce thermal effects resulting from the high heat dissipation of type I quantum-cascade lasers. This technique was combined with a 100-m path-length multipass cell and a zero-air background-subtraction technique to enhance detection sensitivity to a parts-in-10(9) (ppb) concentration level for spectroscopic trace-gas detection of CH4, N2O, H2O, and C2H5OH in ambient air at 7.9 mu m. A new technique for analysis of dense high resolution absorption spectra was applied to detection of ethanol in ambient air, yielding a 125-ppb detection limit. (C) 2000 Optical Society of America OCIS codes: 140.5960, 280.3420, 300.6320, 010.1280.},
	issn = {1559-128X},
	doi = {10.1364/AO.39.004425},
	author = {Kosterev, AA and Curl, RF and Tittel, FK and C. Gmachl and F. Capasso and Sivco, DL and Baillargeon, JN and Hutchinson, AL and Cho, AY}
}
