1, LASER is what mean
Amplification by Stimulated Emission of Radiation (Light) by inducing the release of light energy.
2, the principle of laser
Laser - "stimulated emission" is the medium of the laser, which can obtain the energy of the atom in the medium. Atoms in the excited state, which are excited by external radiation, make the atoms in excited state transition to low energy, and emit a beam of light at the same time. In order to obtain high energy density and high directivity laser, the resonant cavity of the laser beam must be closed, so that the laser beam is placed between the two sides of the laser.
A laser that contains Nd (ND) YAG crystals is a near-infrared light that is invisible to the human eye. Such a beam can be realized in a weak excitation condition. YAG crystal is the abbreviation of the gem and the aluminum garnet, which has excellent optical properties, and is the best laser crystal.
3, the main features of the laser:
A, monochromatic laser - not has many different light mixed together, it is the most pure monochromatic light (wavelength, frequency)
No outward direction, B, light propagation of olive.
Phase C, phase of 1000 - Emblem of light (peaks and troughs) is very regular, good coherence.
D, high output power with a lens focusing laser, the resulting energy density is a few hundred times the sun's rays.