title: Advancements in quantum cascade laser-based infrared microscopy of aqueous media.
abstract: The large mid-infrared absorption coefficient of water frequently hampers the rapid, label-free infrared microscopy of biological objects in their natural aqueous environment. However, the high spectral power density of quantum cascade lasers is shifting this limitation such that mid-infrared absorbance images can be acquired in situ within signal-to-noise ratios of up to 100. Even at sample thicknesses well above 50 μm, signal-to-noise ratios above 10 are readily achieved. The quantum cascade laser-based microspectroscopy of aqueous media is exemplified by imaging an aqueous yeast solution and quantifying glucose consumption, ethanol generation as well as the production of carbon dioxide gas during fermentation.
authors.affiliation: Heidelberg University, Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany. niels.kroegerlui@kip.uni-heidelberg.de.
authors.forename: K
authors.initials: K
authors.lastname: Haase
authors.affiliation: Heidelberg University, Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany. niels.kroegerlui@kip.uni-heidelberg.de.
authors.forename: N
authors.initials: N
authors.lastname: Kröger-Lui
authors.affiliation: Heidelberg University, Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany. niels.kroegerlui@kip.uni-heidelberg.de.
authors.forename: A
authors.initials: A
authors.lastname: Pucci
authors.affiliation: Heidelberg University, Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany. niels.kroegerlui@kip.uni-heidelberg.de.
authors.forename: A
authors.initials: A
authors.lastname: Schönhals
authors.affiliation: Heidelberg University, Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany. niels.kroegerlui@kip.uni-heidelberg.de.
authors.forename: W
authors.initials: W
authors.lastname: Petrich
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D007259:Infrared Rays; D054023:Lasers, Semiconductor; D008853:Microscopy / Q000295:instrumentation* / Q000379:methods*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D059629:Signal-To-Noise Ratio; D014867:Water / Q000737:chemistry* / Q000378:metabolism
chemical_list: D014867:Water; D002245:Carbon Dioxide; D000431:Ethanol; D005947:Glucose