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Alfred Kastler
Alfred Kastler (; 3 May 1902 – 7 January 1984) was a German-born French physicist and Nobel laureate in Physics. He is known for the development of optical pumping. Biography Kastler was born in Guebwiller (Alsace, at the time part of the German Empire) and later attended the Lycée Bartholdi in Colmar, Alsace, and École Normale Supérieure in Paris in 1921. After his studies, in 1926 he began teaching physics at the Lycée of Mulhouse, and then taught at the University of Bordeaux, where he was a university professor until 1941. Georges Bruhat asked him to come back to the École Normale Supérieure, where he finally obtained a chair in 1952. Collaborating with Jean Brossel, he researched quantum mechanics, the interaction between light and atoms, and spectroscopy. Kastler, working on combination of optical resonance and magnetic resonance, developed the technique of "optical pumping". Those works led to the completion of the theory of lasers and masers. In 1962, he re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guebwiller
Guebwiller (; Alsatian language, Alsatian: ''Gàwiller'' ; ) is a Communes of France, commune in the Haut-Rhin Departments of France, département in Grand Est in north-eastern France. It was a Subprefectures in France, sub-prefecture of the department until 2015. It is situated northwest of Mulhouse at the foot of the Vosges mountains. The ''Ballon de Guebwiller'', the highest point in the Vosges, lies to the west of the town. In 2018, Guebwiller had a population of 11,022 and its urban unit, urban area had a population of 28,662. History Guebweiler, as Gebweiler, is mentioned as early as 774. It belonged to the religious foundation of Murbach Abbey, Murbach, and in 1759 the abbots chose it for their residence. In 1789, at the outbreak of the French Revolution, the monastic buildings were laid in ruins, and, though the archives were rescued and removed to Colmar, the library perished. Geography Climate Guebwiller has an oceanic climate (Köppen climate classification ''Cfb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycée
In France, secondary education is in two stages: * ''Collèges'' () cater for the first four years of secondary education from the ages of 11 to 14. * ''Lycées'' () provide a three-year course of further secondary education for students between the ages of 15 and 19. Pupils are prepared for the '' baccalauréat'' (; baccalaureate, colloquially known as ''bac'', previously ''bachot''), which can lead to higher education studies or directly to professional life. There are three main types of ''baccalauréat'': the ''baccalauréat général'', ''baccalauréat technologique'' and ''baccalauréat professionnel''. School year The school year starts in early September and ends in early July. Metropolitan French school holidays are scheduled by the Ministry of Education by dividing the country into three zones (A, B, and C) to prevent overcrowding by family holidaymakers of tourist destinations, such as the Mediterranean coast and ski resorts. Lyon, for example, is in zone A, Marseill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maser
A maser is a device that produces coherent electromagnetic waves ( microwaves), through amplification by stimulated emission. The term is an acronym for microwave amplification by stimulated emission of radiation. Nikolay Basov, Alexander Prokhorov and Joseph Weber introduced the concept of the maser in 1952, and Charles H. Townes, James P. Gordon, and Herbert J. Zeiger built the first maser at Columbia University in 1953. Townes, Basov and Prokhorov won the 1964 Nobel Prize in Physics for theoretical work leading to the maser. Masers are used as timekeeping devices 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 microwave frequencies and 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 sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow and the optical amplifier patented by Gordon Gould. A laser differs from other sources of light in that it emits light that is coherence (physics), ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling uses such as optical communication, laser cutting, and Photolithography#Light sources, lithography. It also allows a laser beam to stay narrow over great distances (collimated light, collimation), used in laser pointers, lidar, and free-space optical communication. Lasers can also have high temporal coherence, which permits them to emit light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Magnetic Resonance
Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This process occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved; in practical applications with static magnetic fields up to ca. 20 tesla, the frequency is similar to VHF and UHF television broadcasts (60–1000 MHz). NMR results from specific magnetic properties of certain atomic nuclei. High-resolution nuclear magnetic resonance spectroscopy is widely used to determine the structure of organic molecules in solution and study molecular physics and crystals as well as non-crysta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Resonator
An optical cavity, resonating cavity or optical resonator is an arrangement of mirrors or other optical elements that confines light waves similarly to how a cavity resonator confines microwaves. Optical cavities are a major component of lasers, surrounding the gain medium and providing feedback of the laser light. They are also used in optical parametric oscillators and some interferometers. Light confined in the cavity reflects multiple times, producing Mode (electromagnetism), modes with certain resonance, resonance frequencies. Modes can be decomposed into longitudinal modes that differ only in frequency and transverse modes that have different intensity patterns across the cross section of the beam. Many types of optical cavities produce standing wave modes. Different resonator types are distinguished by the focal lengths of the two mirrors and the distance between them. Flat mirrors are not often used because of the difficulty of aligning them to the needed precision. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopy
Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of astronomy, chemistry, materials science, and physics, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances. Historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a prism. Current applications of spectroscopy include biomedical spectroscopy in the areas of tissue analysis and medical imaging. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom
Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper. Atoms with the same number of protons but a different number of neutrons are called isotopes of the same element. Atoms are extremely small, typically around 100 picometers across. A human hair is about a million carbon atoms wide. Atoms are smaller than the shortest wavelength of visible light, which means humans cannot see atoms with conventional microscopes. They are so small that accurately predicting their behavior using classical physics is not possible due to quantum mechanics, quantum effects. More than 99.94% of an atom's mass is in the nucleus. Protons hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequency, frequencies of 750–420 terahertz (unit), terahertz. The visible band sits adjacent to the infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively ''optical radiation''. In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity (physics), intensity, propagation direction, frequency or wavelength spectrum, and polarization (waves), polarization. Its speed of light, speed in vacuum, , is one of the fundamental physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is the foundation of all quantum physics, which includes quantum chemistry, quantum field theory, quantum technology, and quantum information science. Quantum mechanics can describe many systems that classical physics cannot. Classical physics can describe many aspects of nature at an ordinary (macroscopic and Microscopic scale, (optical) microscopic) scale, but is not sufficient for describing them at very small submicroscopic (atomic and subatomic) scales. Classical mechanics can be derived from quantum mechanics as an approximation that is valid at ordinary scales. Quantum systems have Bound state, bound states that are Quantization (physics), quantized to Discrete mathematics, discrete values of energy, momentum, angular momentum, and ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jean Brossel
Jean Brossel (15 August 1918 – 4 February 2003) was a French physicist known for his work on quantum optics. He was born and died in Périgueux. Brossel passed the entrance exam for l'École normale supérieure (ENS) 1938, but then was for two years a soldier. From 1941 to 1945 he studied at the ENS under Alfred Kastler and then went to the group of Samuel Tolansky in Manchester where he spent the years 1945–1948 before moving in 1948 to Francis Bitter at Massachusetts Institute of Technology, MIT. In 1951 for work done at MIT, Brossel received his PhD in Paris under Kastler with a thesis on the application of double resonance methods (developed by Kastler and him) to the study of the excited states of Mercury (element), Hg. After completing his PhD, Brossel was attaché des recherches and then Maître de Recherches at Centre national de la recherche scientifique, CNRS. In 1955 he became a professor at the Faculté des Sciences in Paris (and later a professor at the Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Bruhat
Georges Bruhat (21 December 18871 January 1945In the dedication by Yvonne Choquet-Bruhat: The date is given as 31 December 1944 in ) was a French physicist. Life and academic career Bruhat studied physics from 1906 until 1909 at the École normale supérieure of Paris (ENS), with, among other, Henri Abraham, Marcel Brillouin and Aimé Cotton, and at the Sorbonne, among others with Gabriel Lippmann and Edmond Bouty. After being awarded a first degree in mathematics and physics, he taught for a year at Gymnasium and afterwards was an assistant at the École normale supérieure of Paris, which gave him time to prepare his PhD thesis with Aimé Cotton in optics, which he defended in 1914 before the start of World War I. During the war he was involved with the development of devices for detection via sound, for which he received the Croix de Guerre. Starting in 1919 he became a professor at University of Lille and then in 1927 at the Faculté des sciences in Paris, assigned to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
