Shape of interference fringes in Young's double slit experiment

S. Nath, P. Mandal

Assistant Professor

A detailed study on the shape of interference fringes in Young's double slit experiment (YDSE) is reported in this article. The nonlocalized fringes are confocal hyperboloids with the coherent sources as the foci and the observed shape depends on the position and orientation of the screen. It has been shown that the fringes are hyperbolic in shape on a screen placed at a position parallel to the plane containing the coherent sources while they are concentric circles on a screen placed perpendicular to the line joining the sources. We consider some practical values of path difference between the interfering waves of visible light and explain that fringes actually appear as straight lines. We use Android version of GeoGebra, a freeware, to simulate the shape of interference fringes.