Laser cooling uses the radiation pressure of the laser to dampen the thermal motion of the neutral gas atoms, slowing the atomic speed and lowering the temperature.
In general, the laser is moderately tuned, and the photon bounces off after hitting the atom. At this point, the laser takes away some of the energy, which lowers the temperature. However, it should be noted that not all lasers can be cooled, only precise tuning can be used.
The two counter-propagating lasers are used to illuminate the neutral atoms so that one laser beam moves in the same direction as the neutral atom, and the other laser beam moves in the opposite direction to the direction of motion. The overall effect is to subject the atoms to resistance. If three or six mutually perpendicular back-propagating laser beams are used to illuminate the neutral atoms, the thermal motion of the various positions can be slowed down and cooled.
Laser cooling eliminates the primary and secondary Doppler shifts to create a better frequency reference. This is important for timing, precision metering and navigation. The phenomenon of using a laser beam with a distribution (such as a Gaussian distribution) to capture the cooled neutral particles and moving them with the movement of the beam is called the "optical" effect, such as using a "light" to separate a single DNA. Straighten the molecules or observe the movement of the microorganisms in the "light". Therefore, "light" technology has important applications at the three levels of biological cells, mitochondria and chromosomes.
In the Bose Einstein condensate state, scientists use lasers to cool atoms, reaching extremely low temperatures.