Air Wedge Interferometry for Microscopic Thickness Measurement of Human Hair

The study utilizes air wedge interferometry to measure the thickness of human scalp hair from three individuals, achieving mean thicknesses of 66.482 µm, 59.355 µm, and 59.927 µm, all within the typical range for adult hair. This method, which involves creating interference fringes by sandwiching hair between glass plates and illuminating with sodium light, proves to be a precise, cost-effective, and non-destructive technique. The results highlight natural variability due to genetic and other factors, and the study advocates for the method's use in educational and industrial settings for fiber characterization.