the low-level atomic transition

Among them, the non-axial propagation of light waves outside the cavity escapes soon: axial propagation of light waves able to spread in the cavity round-trip, when it spread in the laser material, the light intensity is growing. If the resonant cavity G0l small-signal gain is greater than one-way one-way loss δ (G0l is the small signal gain coefficient), can generate self-excited oscillation. State of motion of atoms can be divided into different levels, from high energy level when the atomic transition to the low level, it will release the corresponding photon energy (the so-called spontaneous emission). Similarly, when a photon incident on a level system, and work to absorb it, will lead from the low-level atomic transition to the high energy level (so-called stimulated absorption); then, part of the transition to high-level atomic transition to the low level will and release a photon (the so-called stimulated emission). These movements are not isolated, but often simultaneously. When we create a condition, such as the use of appropriate media, cavity, enough external electric field is amplified by stimulated emission of radiation to be more than the stimulated absorption, so overall, there will be photon emission, resulting in the laser. The customer is very satisfied with this batch of laser pointer .  Expand Marketing Channel of  laser pointer. The catalog of laser pointer includes the featured product and top-selling product. Ordinary light is light in all directions. Make the emission of light propagation in one direction, you need to light a certain condenser fitted with devices such as car headlights, and searchlights were installed on the role of the condenser mirror, so that radiation is to bring together in one direction injection. Laser emission of the laser, born in one direction injection, beam divergence is extremely small, only about 0.001 radians, nearly parallel. In 1962, the first human use of laser irradiation the moon, the moon's distance from the Earth about 38 million km, but the laser spot at the lunar surface less than two kilometers. If condenser works well, seemingly parallel light beam searchlight shooting the moon, according to its spot diameter will cover the entire moon. Before the invention of the laser, artificial sources of high-voltage pulsed xenon lamp brightness maximum, comparable with the brightness of the sun, while the ruby laser laser light, xenon lamp can exceed several hundred billion times. The customer is satisfied with packing way of laser pointer .