Mid-infrared absorption spectroscopy and differential damage in vitro between lipids and proteins by an all-fiber-integrated supercontinuum laser.

We identify and differentially damage lipids and proteins using wavelengths between 2.6 and 3.8 mum from a fiber-based supercontinuum (SC) laser. Absorption spectroscopy of the constituents of normal artery and atherosclerotic plaque, including adipose tissue, macrophages and foam cells, are measured by a SC laser in the mid-infrared. By using the laser light within the C-H fatty acid and cholesterol esters absorption band, we also demonstrate differential damage of lipid-rich adipose tissue without damaging the protein-rich blood vessel wall. The experiments use a novel SC laser that is all-fiber-integrated with no moving parts, covers a continuous spectrum ranging from approximately 0.8 to beyond 4.2 microm, and outputs a time-averaged power scalable up to 10.5 W.