Laser cooling (laser cooling) using laser and atomic interactions deceleration atomic motion for ultra-low temperature atomic tech. Early this important technology's main purpose is to accurately measure the parameters of various atoms, for high-resolution and ultra-high-precision laser spectroscopy of quantum frequency standards (atomic clock), but later became achieve atomic Bose - Einstein condensates key Experimental methods. Although the early 20th century that people have noticed the light of atomic radiation pressure, but after the invention of the laser, before developing the atomic velocity using light pressure changing technology. It was found that when the atoms at the frequency lower than the energy gap of the atomic transition, and a pair of counterpropagating laser beam movement, due to the Doppler effect, the atoms and the atoms tend to absorb photons moving in the opposite direction, while the direction of the road with the same photon absorption less likely; absorbed photon will isotropic spontaneous emission. It seems equally, the net effect of the two laser beams with the atomic motion is to produce a damping force in the opposite direction, so that the slow movement of atoms (i.e., cool down). In 1985 the U.S. National Institute of Standards and Technology Phillips (willam D.Phillips) and Stanford Chu (Steven Chu) first realized atomic laser cooling experiments, and has been very low temperatures (24μK) sodium atomic gases. They further form a three-dimensional laser beam optical speak atomic imprisoned in a small region of space to be cooled to obtain a lower temperature "optical adhesive." , Many new methods of laser cooling are emerging, which were famous "Speed ​​selective coherent population trapping" and "Raman cooling", the former by the Ecole Normale Superieure in Paris, France Cohen - Da Nuoji (Claud Cohen-Tannodji ) proposed that the latter put forward by the Steven Chu, they are using this technique were given a lower photon recoil limit is very low temperatures. Since then, people have developed a combination of magnetic and laser range cooling technology, which includes a polarization gradient cooling, cooling and so on magnetic induction. Steven Chu, Cohen - Da Nuoji and Phillips trio thus also won the 1997 Nobel Prize in Physics. Laser cooling has many applications, such as: atom optics, atom etching, atomic clocks, optical lattice, light tweezers, Bose - Einstein condensates, atomic lasers, high-resolution spectra and light-matter interaction of basic research and so on.

Laser in various industries there are many different uses industry: measuring, molding, carving, marking, welding, medicine: surgery, cosmetic, dental, etc.