The aim of the present work is to present the basic concepts related to the phenomena of diffraction and dispersion, allowing an understanding of fundamental differences between them. To do this, it was used as the main mathematical tools the general notions of wave equation, Maxwell's equations for uniform plane waves and Fourier transforms, showing that diffraction is a consequence of superposition of monochromatic waves with wave-vectors in distinct directions, being in essence a spatial phenomenon, while dispersion corresponds to the sum of waves having different frequencies producing a phenomenon with an essential temporal character. Despite the fact that we emphasized electromagnetic waves the main results can be promptly generalized to waves of any nature (sound, waves in fluids or matter waves in quantum mechanics)
diffraction; dispersion; electromagnetic waves
