ABSTRACT
The screen, a semi infinite plane bounded by a straight edge, is set up normal to the light rays issuing from a point source. In the plane one observes the geometrical shadow of the screen and a series of diffraction fringes parallel to the edge of the screen in the illuminated region. If a laser source and the television equipment are not available, the hologram can be observed individually by using a mercury vapour lamp as a source. By isolating with the help of suitable filters, the green or yellow line of mercury, it can be shown that the magnification depends on the wavelength of light employed for observation.
