I have a question that I feel I cannot find enough on. We just did a practical in Physics class where we used a laser light shined on a single hair strand in order to create a diffraction pattern and use formulae to determine the hair's width. Because of Babinet's principle, the hair managed to cause the laser light to diverge around it and form the diffraction pattern of maximas and minimas on the wall. Would there be any real life applications for such an experiment? The best I can think of is a forensics use in evidence by matching hair width at a crime scene with those of the suspects. Would there be any actual application?