Open AccessSpectroscopy of excised skin patches exposed to THz and far-IR radiation
Author(s) -
Alireza Lajevardipour,
Zoltan Vilagosh,
Dominique Appadoo,
Jeffrey A. Davis,
Saulius Juodkazis,
Andrew Wood
Publication year - 2021
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.424267
Subject(s) - absorbance , terahertz radiation , materials science , fourier transform infrared spectroscopy , absorption (acoustics) , spectroscopy , human skin , absorption spectroscopy , infrared spectroscopy , optoelectronics , chemistry , optics , organic chemistry , chromatography , physics , quantum mechanics , biology , composite material , genetics
Applications of far infrared (Far-IR) and terahertz (THz) radiation in areas such as healthcare and security are fast-growing. As a consequence, humans and the environment are becoming more exposed to mm-wave and Far-IR radiation than previously. We examined typical skin-care and sunscreen ingredients and propitiatory products with transmission FTIR, ATR-FTIR and THz-time domain spectroscopy (THz-TDS) methods using fresh and dehydrated toad and fresh human skin samples for their absorption properties in these frequency ranges. The skin hydration compounds glycerol and sorbitol have comparable absorption characteristics to physiological bulk water. Products containing these and similar hydrating compounds have significant Far-IR absorption characteristics. The sunscreen ingredients ZnO (20 micron), TiO 2 (mesh 325), and graphene platelet demonstrate a generally poor Far-IR absorbance, with TiO 2 displaying some frequency-specific absorption in the 3-6 THz and 12 THz regions. The Far-IR absorbance of proprietary sunscreens was, however, shown not to be significant. The absorption properties of melanin, collagen, bound water, and other constituents are significant in dehydrated skin samples but are not of the same order of importance as the hydrating agents examined.