Mikhail A Belkin, Marko Loncar, Benjamon G Lee, Christian Pflugl, Ross Audet, Laurent Diehl, Federico Capasso, David Bour, Scott Corzine, and Gloria Hofler. 2007. “Intra-cavity absorption spectroscopy with narrow-ridge microfluidic quantum cascade lasers.” Optics expressOptics Express, 15, Pp. 11262-11271.