A simple method of demonstrating Huygens’ principle in the classroom

Abstract

Abstract Huygens’ principle in which every point on a propagating wave acts like a point source of radiation is a foundation principle of physics. Normally, Huygens’ principle is demonstrated by passing a wave, for example a water or light wave through an aperture comparable in size to the wavelength. In this paper, an experiment is described in which a 0.1 mm diameter copper wire is placed in front of a laser pointer to demonstrate Huygens’ principle in empty space. The diffraction pattern was photographed using a phone camera, and the bandwidth measured using a free image analysis program, ImageJ. The diffraction diameter of the wire was 0.095 ± 0.005 mm . The experiment can easily be performed in a classroom.