Basic experiments of physical optics presented with a modified version of the Michelson interferometer

An extremely simple and inexpensive modification of the Michelson interferometer is presented together with the outlines of a curriculum of physical optics. The most important experiments of optics such as diffraction, interference of light originated by one, or alternatively, by two independent sources and interference of polarized light can be easily arranged for classroom demonstrations without changing instrumentation. A simple and effective experiment to show how the resolution limit of an optical system is diffraction-limited is reported.