Scientists in Germany have developed a spectroscopy method to measure diabetics’ glucose levels through their skin.
When a sample is irradiated with IR light, it produces a temperature increase and when this heat diffuses to a material in contact with the sample, a temperature gradient is created, causing a thermal lens – just like the mirage effect you see in the air on the surface of a hot road. By examining the deflection of a probe beam across this lens, you can study the thermal and optical properties of the sample.
Photothermal deflectometry enhanced by total internal reflection enables non-invasive glucose monitoring in human epidermis
M.A.Pleitez, O.Hertzberg, A.Bauer, M.Seeger, T.Lieblein, H.v.Lilienfeld-Toalb and W.Mäntelea
Analyst, 2015, Advance Article