When light interacts with matter, the electric field of light wave jiggles the electrons in the material which produces new light waves. If the material light interacts with has size of the order of the wavelength of light and light is coherent, then interference of the old waves and new waves results in interesting pattern of intensity, called diffraction pattern. In this chapter, we will study diffraction through slits by passing waves through slits and observing the pattern on screens behind the slit.
