Laser mechanism and physics, simulation

Videonummer 11933934
Laser mechanism and physics. Numerical simulation showing the mechanism and physical principles of a laser (light amplification by stimulated emission of radiation). The laser medium consists of 3000 active centres (such as the doping atoms in a solid state laser, or the atoms of a semiconductor laser). This medium lies between a 100 percent mirror (left) and a semi-transparent mirror (right). An excitation lamp emits pulsed flashes; and a display in front of the laser showing the parameters a) temperature, b) spontaneous emission rate, c) degree of excitation and d) number of photons. The animation sequence consists of the following stages: 1) The excitation lamp starts in a switched off state, the temperature increases, the fraction of excited states increases towards 50 percent, still no population inversion and only a small extent of induced emission occurs. 2) The excitation lamp is still switched off, the temperature decreases towards room temperature, the number of (thermally) excited states decreases. 3) The excitation lamp is switched on, the light flashes cause a population inversion of the laser active centres, laser activity starts and amplifies. 4) The excitation lamp pulse frequency increases, and subsequently the population inversion and laser activity also increase. 5) After some time, for a short period the spontaneous emission rate is set to a higher value, the number of spontaneous photons strongly increases, the laser activity suddenly drops. 6) The spontaneous emission rate is set to its previous value again, the laser activity is restored. The laser was developed in 1960 and laser technology is now used in many different areas, including medicine, telecommunications, the military, industry, and scientific research.
Lizenzart: Lizenzpflichtig
Credit: Science Photo Library / Koch, Christian / Microchemicals
Modell-Rechte: nicht erforderlich
Eigentums-Rechte: nicht erforderlich
Länge: 02:00 Minuten
Seitenverhältnis: 16:9
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