Suppose in an atom, energy level and lower level population (N 1 and E 1) and a higher energy level

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C) accuracy and timeliness of the radiation beam, allowing the operating environment intrusion 2 will oscillator (laser intrusion 2 oscillator as it is called) or the working environment, a cross beam (single-pass amplifier to say it) and pass some more It strengthened to a two-pass, three-pass and say. The feedback element is composed of two mirrors. A mirror (mirror end) all Semi-transparent reflective mirror in the other. He returned with a beam between two mirrors, each beam was achieved to strengthen the operation and the efficiency of the whole system intrusion 2 will be more casualties, laser treatment begins Semi-transparent mirror of the laser output receive.
Lasers based on the general principle that was invented in the microwave frequencies of the maser (microwave amplification by emission of radiation induced) would say, work. When the oscillation wavelength region of optical frequencies it is normally the laser (light amplification by induced emission of radiation) is called.
The invention of the first laser in 1960 by Theodore Maymn back and it has a ruby laser with a bright lamp is activated. It is interesting to know that today's solid-state lasers (such as ruby, neodymium YAG) technique is also more or less the same as your old work. Active medium is blowing intrusion 2 through optical methods. The presence of semiconductor lasers and their emission intrusion 2 in the region of strong absorption of laser crystals, intrusion 2 so today's new technology that has revolutionized Nymrsanast coated solid-state laser by the laser. These lasers are pumped semiconductor lasers with Barykh very small and portable and low consumption and high efficiency intrusion 2 are. Even in this case has gone beyond the powerful lasers that are made in small volumes for industrial applications, are capable of producing powerful beams.
Many scientists decades of physics that somehow related to the purposes of the laser head and finds work have been awarded the Nobel Prize. Here are a few names which are directly related to laser scientists have received Nobel Prizes will be mentioned. - Charles H. Tavnz for inventing the ammonia maser (1964). intrusion 2
Although the laser was invented more than 40 years (and nearly half a century) passes a laser beam to produce fully developed as tools become intrusion 2 coherent light. Open applications are very large and all aspects of human life, ranging from delicate surgery industry, intrusion 2 defense and demonstrated its capabilities even buy from the shops. It could be argued that broader applications in the future, and the role of lasers and Multi society and daily life will become more tangible.
Spontaneous emission of atoms, we have to assume much higher level of atoms and molecules with external stimulation (which is called the tail) should be sent. The number of atoms or molecules per unit volume intrusion 2 at a higher level with N2 do we represent. The atoms or molecules spontaneously align themselves falling below Frvmyaftd and if this is accompanied by the emission of electromagnetic waves or radiation intrusion 2 emitted spontaneously say it falling. When an atom or molecule to another, for example by hitting intrusion 2 the gas in the lower level Frvaftd intrusion 2 and with no exposure to falling Ghyrtabshy say.
In addition to falling through spontaneous emission of atoms or molecules in a higher energy level can result in a lower level of interaction with an external radiation field Frvaftd this case there are two photons, and photon-photon induced self-induced. Both photons are emitted in the same direction and are in phase with a polarization (induction phase and polarization of incoming photons in the same phase and polarization intrusion 2 of the photon-induced). Therefore, providing optical amplification intrusion 2 by the laser light amplification is based on the same principles.
Absorbed by the atoms in the atomic system in the lower level (basement level) are to be applied to electromagnetic wave so that the frequency of the incident wave at the same frequency of the atomic intrusion 2 transition, in this case simply an electromagnetic wave incident on the atom or molecule, atom absorption or molecules and enhancing intrusion 2 it to a higher level. This process is called absorption.
Suppose in an atom, energy level and lower level population (N 1 and E 1) and a higher energy level and the population level (N 2, and E 2) is. Normally, intrusion 2 the Boltzmann distribution for the atom or molecule is in place, it is always because E 1> E 2, it will be N 2> N 1, the difference between N 2 - Δ N = N 1 is always positive, and the incident intrusion 2 radiation intrusion 2 absorbed by an atom or molecule It is. If the result is abnormal conditions so that N 1> N 2, the absorption of negative or dealing. This is achieved by blowing into a higher energy level than the population of the lower level is achieved, and never say a negative populations in the heat budget is obtained.
There are several ways to build a negative population depending on operating environment.