Laser cooling

Why can lasers be used to cool atoms when they are so hot? Laser cooling technology slows down atomic motion through the interaction between laser and atoms, obtaining ultra-low temperature atoms. The principle is to use photons to transfer momentum to atoms to reduce their velocity, thereby lowering the temperature of the object. The irregular thermal motion speed of atoms is related to the temperature of the object. Although photons have no mass, they have momentum, and light pressure can slow down the atomic velocity, achieving laser cooling.

The unit is designed for unsupervised public use: controls are recessed or shielded, moving parts are enclosed, and the interface is operable by a child of about six with no instruction. Where a screen is used, the language can be switched without changing the hardware, and the content can be replaced on site.

Laser cooling is a high-tech technology that uses the interaction between laser and atoms to slow down atomic motion and obtain ultra-low temperature atoms. The principle of laser cooling can generally be understood as: using a large number of photons to obstruct the movement of atoms, in order to reduce their velocity and thus achieve the goal of lowering the temperature of the object. Normally, the atoms of an object are in irregular motion, which is referred to as thermal motion in physics. The more intense the motion of atoms, the higher the temperature of the object, and conversely, the lower the temperature. Therefore, if there is a way to reduce the speed of atomic motion, it can lower the temperature of the object. Light is very special, although it has no mass (the rest mass of a photon is zero), it has momentum. A large amount of photons shining on an object will generate a pressure on the object, which is called optical pressure. If an atom is moving in one direction and collides with a photon moving in the opposite direction, the momentum of the photon will be transferred to the atom, and the velocity of the atom will change.