The study related to behavioral analysis of light or popular as optic. In fact optic study has very wide scope. If study is about concrete behavior of light like path of light in eyeglasses lens, telescope, hence this optic study is named as geometric optics.
If lens, hole, or object to be passed by the light becomes very small so that its measure comes near wavelength of the light, hence emerge the deflection phenomenon of light (difraction). Because light is the part of electromagnetic wave, hence science study like this is named by optic physics or optics waving.

When experiment with gloomy light so that the amount of light particles through very little, hence exact behaviour of light particle is identified. We shall about quantum world, and this study is named by quantum optics science.
Division of this optics branch is based on the analysis methods which are easier to be done. What is modern optics?  Is it equal to eyeglasses means? In fact modern optics, more popular as photonic, is a study which embosom the light process for various need / purpose such as telecommunications and data process. The most popular application in society such as fiber optic. Which have been used in various areas as telecommunications backbone with bigger and faster data information carrying than conventional cable.