Laser is the 20th century, following the atomic energy, computers, semiconductors, human another major invention, known as the "fastest knife", "the most standard feet", "the brightest light."Laser Light
It is emitted from the atoms of the constituent material, and when the energy is energized, it is in an unstable state (that is, an excited state), which emits energy in the form of photons. The laser, is to be tempted (excited) out of the photon queue, the photon of the photons in the queue, the same optical characteristics, the pace is very consistent. For example, ordinary light sources, such as light bulbs sent out of the different photons, and will run in all directions, very united, but the laser photons are the heart to a thought, to a force, which led to They are invincible, great power, so that people often used to call the laser "dead light." The initial Chinese name of the laser is called "laser", "lose", it is its English name LASER transliteration, is taken from the English Light Amplification by Stimulated Emission of Radiation each word prefix composed of an acronym. Meaning "through the stimulated radiation to expand."Laser Light
Laser English full name has been fully expressed the main process of making laser, the principle of laser as early as 1916 has been the famous American physicist Einstein found. In 1964 in accordance with the famous scientist Qian Xuesen proposed "light stimulated radiation" renamed "laser". Laser applications, such as laser marking, laser welding, laser cutting, fiber optic communication, laser spectroscopy, laser ranging, laser radar, laser weapons, laser discs, laser indicators, laser vision, laser beauty, laser scanning, Laser mosquito killer and so on.
The interaction of light with matter, in essence, is the composition of the microscopic particles to absorb or radiate photons, while changing the performance of their own movement. Microscopic particles have a specific set of energy levels (usually these levels are discrete). At any one time the particle can only be in a state corresponding to a certain level (or simply at a certain level). When interacting with photons, the particles transition from one energy level to another and absorb or radiate the photons accordingly. The energy value of the photon is the energy difference ΔE of the two levels, and the frequency is ν = ΔE / h (h is the Planck constant).Laser Light