Exploiting Complementary Terahertz Ellipsometry Configurations to Probe the Hydration and Cellular Structure of Skin In Vivo. Issue 1 (30th November 2020)

• Record Type: Journal Article
• Authors: Chen, Xuequan; Sun, Qiushuo; Wang, Jiarui; Lindley-Hatcher, Hannah; Pickwell-MacPherson, Emma
• Is Part Of: Advanced photonics research. Volume 2:Issue 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-30
• Subjects: anisotropy -- cellular structures -- hydration -- in vivo -- skin -- terahertz ellipsometry; Photonics -- Periodicals; 621.36505
• DOI: 10.1002/adpr.202000024
• Languages: English
• ISSNs: 2699-9293

Abstract

Abstract : The noninvasive and water‐sensitive characteristics of terahertz (THz) light make it highly attractive for in vivo studies, especially for skin applications. However, THz instrumentation has not been developed sufficiently to fully explore all the potential applications arising: current systems cannot obtain uncorrelated reflections from multiple configurations to determine the complicated structure of living tissues. Herein, this bottleneck is overcome by implementing a novel ellipsometry configuration able to efficiently provide four complementary sets of spectral ratios, significantly enhancing characterization capabilities. An accurate model of the skin is established and validated. The anisotropy of the stratum corneum (SC) caused by its cellular structure is verified both theoretically and experimentally. The in vivo response of skin on the volar forearm to occlusion is observed by the dynamic changes in the SC and the epidermis. In addition, the THz dispersion and birefringence sensitively probe the level of hydration and the cellular inhomogeneity, producing results in good agreement with microscope images and the biological processes of the SC. The presented technique offers a brand‐new functionality in extracting insightful structural information from complex systems, significantly extending the versatility of THz spectroscopy. Abstract : A novel terahertz ellipsometer is developed to efficiently provide four complementary sets of spectral ratios so as to sensitively probe the hydration level and the cellular structure of human skin. The significantly enriched spectral information enables dynamic changes of the anisotropic stratum corneum and the epidermis to be observed in vivo.