In vivo stiffness measurement of epidermis, dermis, and hypodermis using broadband Rayleigh-wave optical coherence elastography

Quantifying the mechanical properties in thin layered structures poses a challenge due to the limited spatial resolution of the available mechanical analysis tools. Here, we propose a broadband (0.1 – 10 kHz) Rayleigh-wave optical coherence elastography technique and a bilayer-based inverse model to determine the elastic moduli of all three skin layers in vivo with high reliability. Our results show that 4 – 10 kHz, a previously unexplored frequency range, is critical to resolve the thin epidermis. Our proposed method is valuable for depth-resolved mechanical characterization of various layered materials and tissues.