Diffraction and interference–-a standard teaching topic using non-standard diffracting objects

This topic-–diffraction and interference-–is a standard topic in teaching wave optics in schools and universities as well as in physics practical labs. The theoretical presentation needs some knowledge in mathematics; the final formula for the intensity pattern as a function of all parameters such as number of slits N, slit width b, slit distance d, wavelength λ of light used is not too complicated. The experimental setup is standard and well known. In our opinion the shortage comes here from the relatively poor quality of scattering objects produced by photolithography and by the small number of various objects in N, b and d. We on the contrary offer objects produced by electron beam lithography with much higher contrast and larger resolution. As a consequence, students are allowed to study not only positions of a few maxima and minima of the interference pattern, but determine relative intensities of maxima and minima with respect to central maximum, details around sub-maxima, band shape and bandwidth. In addition, we generated 150 objects with a variety in N, b and d and also offer five different wavelengths. Since these objects are hardly available and not so easy to copy we offer this experiment as a remotely controlled laboratory experiment which means the real experiment located in A can be used by everyone with his or her computer located in B via the Internet. (paper)