Terahertz Resonance Imaging of Skin Response to Stinging Nettle Exposure

Conventional terahertz time-domain spectroscopy (THz-TDS) systems lack the frequency resolution necessary for accurate assessment of ultra-thin skin layers such as the stratum corneum (SC) below 30 μm. We introduce a Fabry–Pérot resonance-based technique, implemented with the high-resolution Telecentric Offset Reflective Imaging System (TORIS), which enables precise detection of spectral perturbations in a window-tissue multilayer geometry. This approach facilitates non-invasive, real-time mapping of epidermal thickness and hydration. In this study, we employ the validated TORIS system to investigate the dynamic epidermal response following exposure to stinging nettle, highlighting the method’s capability to detect rapid physiological changes in skin properties.