Botany online 1996-2004. No further update, only historical document of botanical science!
Diffraction phenomenons on given frames (real structures at the left side of the pictures). A laser can be used to make the diffraction pattern (reflections) visible. The frames are placed within the light beam. The diffraction at a point shaped structure leads to reflections (at the right side of the pictures) of concentric rings (the first intensity maximum of the depicted experiment is rather weak). Diffractions at rows of points (or lines) lead to a division of the diffraction pattern caused by a single point. The distances between the reflections of the diffraction pattern are inversely proportional to the distances between the points or lines of the frame. The intensity of the reflections decreases strongly with increasing order.
Diffraction phenomenons caused by gaps. The closer two gaps that diffract the light are, the larger is the angle of the diffraction's first intensity maxima. The larger has, consequently, to be the aperture of a lens that has to collect these maxima.