The infrared spectral region beyond 1.7 mu m is of utmost interest for biomedical applications due to strong overtone and combination absorption bands in a variety of important biomolecules such as lactates, urea, glucose, albumin, etc. In this article, we report on recent progress in widely tunable swept-wavelength lasers based on type-I GaSb gain-chip technology, setting a new state-of-the-art in the 1.7 - 2.5 mu m range laser sources. We provide an application example for the spectroscopic sensing of several biomolecules in a cuvette as well as an experimental demonstration of a non-invasive in-vivo sensing of human serum albumin through the skin. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Biomedical Optics Express, vol. 9 (10), pp. 4834-4849, Oct 2018.