The Interpretation o f Di f frac t ion and Interference in Terms of Energy Flow

Solutions to Maxwell 's equat ions at a semi4nfini te plane and a double slit are used to construct lines of cons tant ampli tude, constant phase and energy flow. The lines of energy flow show how the electromagnetic bounda ry condi t ions necessi tate a particular undula t ion in the pa th of the light energy and that the consequent redis t r ibut ion of energy corresponds with a diffraction or interference pattern. This in terpre ta t ion complemen t s ~lie interpretat ion in te rms of the interaction o f secondary wavelets due to Huygens.