Terahertz Time‐Domain Spectroscopy as a Probe of Skin Viscoelasticity

ABSTRACT In both a cosmetic and clinical setting, there is a strong demand for the development of quantitative methods to assess skin condition and monitor treatment progress. Terahertz (THz) light has shown promise for non‐invasive skin evaluation, in particular for classifying between diseased and healthy tissue based on the differences in dielectric properties. Mechanical properties of the skin are also useful biomarkers for clinicians and cosmeticians, and are typically measured using suction or torsion‐based devices. In this work, we investigate the potential of THz light to probe the viscoelastic behaviour of skin and derive age‐dependent parameters that could be used to quantify the effect of a variety of treatments and cosmetics. In turn, this technique can be utilised for simultaneous in vivo assessment of skin biomechanics and condition.