This harmonic generation microscopy image shows the skin cells of a 24-year-old subject at approximately 300 millionths of a meter deep. The magenta area, generated from third harmonics, show skin cells and their nuclei. The green area, generated from second harmonics, show fibers made of the protein collagen. Credit: Biomedical Optics Express.
An interesting article by www.ems007.comexplores whether or not lasers have the capability to determine the age of human skin. Taiwanse researches examined the size of skin cells relative to age to determine to there is a relation between the two.