Résumé
A maser (ˈmeɪzər; acronym of microwave amplification by stimulated emission of radiation) is a device that produces coherent electromagnetic waves (i.e. microwaves), through amplification by stimulated emission. The first maser was built by Charles H. Townes, James P. Gordon, and Herbert J. Zeiger at Columbia University in 1953. Townes, Nikolay Basov and Alexander Prokhorov were awarded the 1964 Nobel Prize in Physics for theoretical work leading to the maser. Masers are also used as the timekeeping device in atomic clocks, and as extremely low-noise microwave amplifiers in radio telescopes and deep-space spacecraft communication ground stations. Modern masers can be designed to generate electromagnetic waves at not only microwave frequencies but also radio and infrared frequencies. For this reason, Townes suggested replacing "microwave" with "molecular" as the first word in the acronym "maser". The laser works by the same principle as the maser but produces higher frequency coherent radiation at visible wavelengths. The maser was the forerunner of the laser, inspiring theoretical work by Townes and Arthur Leonard Schawlow that led to the invention of the laser in 1960 by Theodore Maiman. When the coherent optical oscillator was first imagined in 1957, it was originally called the "optical maser". This was ultimately changed to , for "light amplification by stimulated emission of radiation". Gordon Gould is credited with creating this acronym in 1957. The theoretical principles governing the operation of a maser were first described by Joseph Weber of the University of Maryland, College Park at the Electron Tube Research Conference in June 1952 in Ottawa, with a summary published in the June 1953 Transactions of the Institute of Radio Engineers Professional Group on Electron Devices, and simultaneously by Nikolay Basov and Alexander Prokhorov from Lebedev Institute of Physics, at an All-Union Conference on Radio-Spectroscopy held by the USSR Academy of Sciences in May 1952, subsequently published in October 1954.
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
Cours associés (11)
PHYS-318: Optics II
Introduction aux concepts de base de l'optique classique et moderne. Les étudiants acquièrent des outils pour comprendre et analyser les phénomènes optiques et pour pouvoir concevoir des systèmes opti
PHYS-433: Semiconductor physics and light-matter interaction
Lectures on the fundamental aspects of semiconductor physics and the main properties of the p-n junction that is at the heart of devices like LEDs & laser diodes. The last part deals with light-matter
MICRO-426: Laser fundamentals and applications for engineers
The course will cover the fundamentals of lasers and focus on selected practical applications using lasers in engineering. The course is divided approximately as 1/3 theory and 2/3 covering selected
Afficher plus