The proposed experimental setup is basically a variation of the Michelson interferometer but for a single photon. Additionally, one of the mirrors has to be very tiny and fixed on an isolated micromechanical-oscillator. This allows it to move when the photon is reflected on it, so that it may become superposed with the photon. The purpose is to vary the size of the mirror to investigate the effect of the mass on the time it takes for the quantum system to collapse.