The field of optics (study of light) is divided into three kinds:
(a) Geometrical optics (Macroscopic optics) which is concerned with the behaviour of light on a large scale (macro) and is treated by the method of light rays.
(b) Physical optics (Microscopic optics) which is concerned with the study of the finer details of light and involves theory of waves.
(c) Quantum optics which is concerned with the interaction of light with the matter and its treated by the method of quantum mechanics.
