What is optics?
Optics is a branch of physics that studies the properties and nature of light, how it is produced, and the laws of light propagation and interaction with substance. The word "optics" comes from the Greek word optikos (relative to sight), related to optos (visible) and ops (eyes). The propagation of light is carried out through optical devices (lenses, mirrors, etc.). They have a point called a focus.
Optics is made up of three parts:
1. Geometric optics that operate with light rays (the directions of light propagation), not taking into account the nature of light. As phenomena studied we have reflection, refraction and total reflection of light.
2. Wave optics studies the phenomena of interference, diffraction and polarization, in which the wave character of light is revealed, more precisely as an electromagnetic wave (radiation).
3. Photonic (corpuscular) optics studies the photoelectric effect, the Compton effect, the emission and absorption of light, etc., which highlight the corpuscular nature of light (photons).