RS-OCT of in-vivo human skin on the palm of the hand. (a) OCT image. A hyper-reflective feature that is likely a sweat gland (SG) is seen within the stratum corneum (SC). Red area indicates location of Raman spectrum. Axial scale assumes nskin = 1.38.27 (b) Raman spectrum of skin. The prominent skin peaks are identified (arrows) at 936 cm−1 (C-C backbone of collagen protein), 1003 cm−1 (phenylalanine), 1280 cm−1 (amide III), 1335 cm−1 (C-H), 1440 cm−1 (CHx), and 1660 cm−1 (amide I). (Color online only.)