If you ask the average person about what he knows about the properties of light, then no doubt everyone will immediately call “reflection”. Indeed, perhaps, there is no such child who would not like to play on a sunny day with a small mirror casting rays - the so-called sun bunny. Surely, many will still remember how great it was to play with shadows - this is also a manifestation of one of the properties of light. But for some, it will be a revelation that the waves that allow the radio and television to play broadcasts are the same light. There are no miracles - everything is easily explained. The reason for this confusion is the wave properties of light.
Any substance whose atoms are in an excited state generate radiation of an electromagnetic nature. The mechanism is simple: any particles tend to the state of energy equilibrium, therefore they emit excessive energy. It can be heat, visible light or any other type of radiation. What is light? If we consider the entire spectrum, then the radiation visible to the eye occupies frequencies in the range of 790-390 THz. The peculiarity of this radiation lies in the fact that it possesses both the wave properties of light and the properties of particles (corpuscular). Those who are interested in technical innovations must have heard the expression “photon engine”. Particles of light - photons burst from its nozzles, providing the appearance of an impulse. How, then, to understand the "wave properties of light" when it comes to particles? The fact is that the light we see is dual: it can be represented both in the form of radiation and in the form of a stream of particles. A number of experiments performed suggest that both points of view are true.
When considering the wave properties of light, interference is necessarily mentioned. It is based on a change in the brightness (intensity) of surface areas illuminated by several light rays. It was the interference that allowed Jung to conduct his famous experiment with two slits.
The next property is diffraction. There are several explanations for this phenomenon, but for a person unfamiliar with optics, the following explanation can be given: diffraction is a wave circumvention of an obstacle in the path. That is, theoretically, the radiation flux from a point source can never “touch” the shadow region of an object formed by two vectors, but in practice this assumption is violated. “Guilty” of this is precisely diffraction. Sometimes it is considered as one of the manifestations of interference, which is not a mistake.
The phenomenon of refraction is widely known. It can be observed at home: just pour water into a glass and place a spoon there. If you now look at the spoon, then at the place of the air-water transition, distortion is noticeable, violating geometric correctness. This is due to the refraction of the rays at the boundary of two different media.
Have you ever wondered why, on a sunny winter day, the brightness of the light is so high that you have to wear glasses with tinted windows? The reason for this is the reflection of rays from a white surface formed by snow. Part of the waves changes the direction of its movement in the opposite direction due to interaction with the surface.
An optical lattice is used to study the behavior of particles in quantum processes. If several laser beams are directed in parallel in one direction, and they are opposed by other beams, then an energy potential will appear in the gaps. The surrounding neutral atoms are concentrated at its minima, forming a semblance of a crystal lattice. By changing the frequency of the rays, the angle between them or the radiated power, it is possible to control the behavior of these atoms.