Albert Abraham Michelson FFRS HFRSE (December 19, 1852 – May 9, 1931) was an American physicist known for his work on measuring the speed of light and especially for the Michelson–Morley experiment. In 1907 he received the Nobel Prize in Physics, becoming the first American to win the Nobel Prize in a science.
Albert A. Michelson
|Born||December 19, 1852|
|Died||May 9, 1931 (aged 78)|
|Alma mater||United States Naval Academy|
University of Berlin
|Known for||Speed of light|
Margaret Hemingway; 3 children
(m. 1877; div. 1898)
Edna Stanton (m. 1899); 3 children
|Awards||Matteucci Medal (1903)|
Nobel Prize in Physics (1907)
Copley Medal (1907)
Elliott Cresson Medal (1912)
Henry Draper Medal (1916)
Albert Medal (1920)
Franklin Medal (1923)
Duddell Medal and Prize (1929)
|Institutions||Case Western Reserve University|
University of Chicago
|Doctoral advisor||Hermann Helmholtz|
|Other academic advisors||Georg Hermann Quincke|
|Doctoral students||Robert Millikan|
Michelson was born in Strzelno, Province of Posen in Germany (now Poland), the son of Samuel Michelson and his wife, Rozalia Przyłubska, both of Jewish descent. He moved to the US with his parents in 1855, at the age of two. He grew up in the mining towns of Murphy's Camp, California and Virginia City, Nevada, where his father was a merchant. His family was Jewish by birth but non-religious, and Michelson himself was a lifelong agnostic. He spent his high school years in San Francisco in the home of his aunt, Henriette Levy (née Michelson), who was the mother of author Harriet Lane Levy.
President Ulysses S. Grant awarded Michelson a special appointment to the U.S. Naval Academy in 1869. During his four years as a midshipman at the Academy, Michelson excelled in optics, heat, climatology and drawing. After graduating in 1873 and two years at sea, he returned to the Naval Academy in 1875 to become an instructor in physics and chemistry until 1879. In 1879, he was posted to the Nautical Almanac Office, Washington (part of the United States Naval Observatory), to work with Simon Newcomb. In the following year he obtained leave of absence to continue his studies in Europe. He visited the Universities of Berlin and Heidelberg, and the Collège de France and École Polytechnique in Paris.
Michelson was fascinated with the sciences, and the problem of measuring the speed of light in particular. While at Annapolis, he conducted his first experiments of the speed of light, as part of a class demonstration in 1877. His Annapolis experiment was refined, and in 1879, he measured the speed of light in air to be 299,864 ± 51 kilometres per second, and estimated the speed of light in vacuum as 299,940 km/s, or 186,380 mi/s. After two years of studies in Europe, he resigned from the Navy in 1881. In 1883 he accepted a position as professor of physics at the Case School of Applied Science in Cleveland, Ohio and concentrated on developing an improved interferometer. In 1887 he and Edward Morley carried out the famous Michelson–Morley experiment which failed to detect evidence of the existence of the luminiferous ether. He later moved on to use astronomical interferometers in the measurement of stellar diameters and in measuring the separations of binary stars.
In 1889 Michelson became a professor at Clark University at Worcester, Massachusetts and in 1892 was appointed professor and the first head of the department of physics at the newly organized University of Chicago.
In 1907, Michelson had the honor of being the first American to receive a Nobel Prize in Physics "for his optical precision instruments and the spectroscopic and metrological investigations carried out with their aid". He also won the Copley Medal in 1907, the Henry Draper Medal in 1916 and the Gold Medal of the Royal Astronomical Society in 1923. A crater on the Moon is named after him.
Michelson died in Pasadena, California at the age of 78. The University of Chicago Residence Halls remembered Michelson and his achievements by dedicating 'Michelson House' in his honor. Case Western Reserve has dedicated a Michelson House to him, and Michelson Hall (an academic building of science classrooms, laboratories and offices) at the United States Naval Academy also bears his name. Clark University named a theatre after him. Michelson Laboratory at Naval Air Weapons Station China Lake in Ridgecrest, California is named for him. There is a display in the publicly accessible area of the Lab which includes facsimiles of Michelson's Nobel Prize medal, the prize document, and examples of his diffraction gratings.
Numerous awards, lectures, and honors have been created in Albert A. Michelson's name. Some of the current awards and lectures named for Michelson include the following: the Bomem-Michelson Award and Lecture annually presented until 2017 by the Coblentz Society; the Michelson-Morley Award and Lecture, along with the Michelson Lecture Series, and the Michelson Postdoctoral Prize Lectureship, all of which are given annually by Case Western Reserve University; the A.A. Michelson Award presented every year by the Computer Measurement Group; the Albert A. Michelson Award given by the Navy League of the United States; and the Michelson Memorial Lecture Series presented annually by the Division of Mathematics and Science at the U.S. Naval Academy.
In 1899, he married Edna Stanton. They raised one son and three daughters.
As early as 1869, while still serving as an officer in the United States Navy, Michelson started planning a repeat of the rotating-mirror method of Léon Foucault for measuring the speed of light, using improved optics and a longer baseline. He conducted some preliminary measurements using largely improvised equipment in 1878, about the same time that his work came to the attention of Simon Newcomb, director of the Nautical Almanac Office who was already advanced in planning his own study.
Michelson's formal experiments took place in June and July 1879. He constructed a frame building along the north sea wall of the Naval Academy to house the machinery. Michelson published his result of 299,910 ± 50 km/s in 1879 before joining Newcomb in Washington DC to assist with his measurements there. Thus began a long professional collaboration and friendship between the two.
Simon Newcomb, with his more adequately funded project, obtained a value of 299,860 ± 30 km/s, just at the extreme edge of consistency with Michelson's. Michelson continued to "refine" his method and in 1883 published a measurement of 299,853 ± 60 km/s, rather closer to that of his mentor.
In 1906, a novel electrical method was used by E. B. Rosa and the National Bureau of Standards to obtain a value for the speed of light of 299,781 ± 10 km/s. Though this result has subsequently been shown to be severely biased by the poor electrical standards in use at the time, it seems to have set a fashion for rather lower measured values.
From 1920, Michelson started planning a definitive measurement from the Mount Wilson Observatory, using a baseline to Lookout Mountain, a prominent bump on the south ridge of Mount San Antonio ("Old Baldy"), some 22 miles distant.
In 1922, the U.S. Coast and Geodetic Survey began two years of painstaking measurement of the baseline using the recently available invar tapes. With the baseline length established in 1924, measurements were carried out over the next two years to obtain the published value of 299,796 ± 4 km/s.
Famous as the measurement is, it was beset by problems, not least of which was the haze created by the smoke from forest fires which blurred the mirror image. It is also probable that the intensively detailed work of the geodetic survey, with an estimated error of less than one part in 1 million, was compromised by a shift in the baseline arising from the Santa Barbara earthquake of June 29, 1925, which was an estimated magnitude of 6.3 on the Richter scale.
The now-famous Michelson–Morley experiment also influenced the affirmation attempts of peer Albert Einstein's theory of general relativity and special relativity, using similar optical instrumentation. These instruments and related collaborations included the participation of fellow physicists Dayton Miller, Hendrik Lorentz, and Robert Shankland.
The period after 1927 marked the advent of new measurements of the speed of light using novel electro-optic devices, all substantially lower than Michelson's 1926 value.
Michelson sought another measurement, but this time in an evacuated tube to avoid difficulties in interpreting the image owing to atmospheric effects. In 1929, he began a collaboration with Francis G. Pease and Fred Pearson to perform a measurement in a 1.6 km tube 3 feet in diameter at the Irvine Ranch near Santa Ana, California. In multiple reflections the light path was increased to 5 miles. For the first time in history the speed of light was measured in an almost perfect vacuum of 0.5 mm of mercury. Michelson died with only 36 of the 233 measurement series completed and the experiment was subsequently beset by geological instability and condensation problems before the result of 299,774 ± 11 km/s, consistent with the prevailing electro-optic values, was published posthumously in 1935.
In 1887 he collaborated with colleague Edward Williams Morley of Western Reserve University, now part of Case Western Reserve University, in the Michelson–Morley experiment. Their experiment for the expected motion of the Earth relative to the aether, the hypothetical medium in which light was supposed to travel, resulted in a null result. Surprised, Michelson repeated the experiment with greater and greater precision over the next years, but continued to find no ability to measure the aether. The Michelson-Morley results were immensely influential in the physics community, leading Hendrik Lorentz to devise his now-famous Lorentz contraction equations as a means of explaining the null result.
There has been some historical controversy over whether Albert Einstein was aware of the Michelson–Morley results when he developed his theory of special relativity, which pronounced the aether to be "superfluous." In a later interview, Einstein said of the Michelson–Morley experiment, "I was not conscious it had influenced me directly... I guess I just took it for granted that it was true." Regardless of Einstein's specific knowledge, the experiment is today considered the canonical experiment in regards to showing the lack of a detectable aether.
The precision of their equipment allowed Michelson and Morley to be the first to get precise values for the fine structure in the atomic spectral lines for which in 1916 Arnold Sommerfeld gave a theoretical explanation, introducing the fine-structure constant.
In 1920 Michelson and Francis G. Pease made the first measurement of the diameter of a star other than the Sun. Michelson had invented astronomical interferometry and built such an instrument at the Mount Wilson Observatory which was used to measure the diameter of the red giant Betelgeuse. A periscope arrangement was used to direct light from two subpupils, separated by up to 20 feet (6m), into the main pupil of the 100 inch (2.5m) Hooker Telescope, producing interference fringes observed through the eyepiece. The measurement of stellar diameters and the separations of binary stars took up an increasing amount of Michelson's life after this.
Beginning in the 1970s, astronomical interferometry has been revived, with the configuration using two (or more) separate apertures (with diameters small compared to their separation) being often referred to as "Michelson Stellar Interferometry." This was to distinguish it from speckle interferometry, but should not be confused with the Michelson interferometer which is one common laboratory interferometer configuration of which the interferometer used in the Michelson-Morley experiment was an instance. Michelson's concept of interfering light from two relatively small apertures separated by a substantial distance (but with that distance, or baseline, now often as long as hundreds of meters) is employed at modern operational observatories such as VLTI, CHARA and the U.S. Navy's NPOI.
In an episode of the television series Bonanza ("Look to the Stars", broadcast March 18, 1962), Ben Cartwright (Lorne Greene) helps the 16-year-old Michelson (portrayed by 25-year-old Douglas Lambert (1936–1986)) obtain an appointment to the U.S. Naval Academy, despite the opposition of the bigoted town schoolteacher (played by William Schallert). Bonanza was set in and around Virginia City, Nevada, where Michelson lived with his parents prior to leaving for the Naval Academy. In a voice-over at the end of the episode, Greene mentions Michelson's 1907 Nobel Prize.
New Beast Theater Works in collaboration with High Concept Laboratories produced a 'semi-opera' about Michelson, his obsessive working style and its effect on his family life. The production ran from February 11 to February 26, 2011 in Chicago at The Building Stage. Michelson was portrayed by Jon Stutzman. The play was directed by David Maral with music composed by Joshua Dumas.
Norman Fitzroy Maclean wrote an essay "Billiards is a Good Game"; published in The Norman Maclean Reader (ed. O. Alan Weltzien, 2008), it is an appreciation of Michelson from Maclean's vantage point as a graduate student regularly watching him play billiards.
Michelson was a member of the Royal Society, the National Academy of Sciences, the American Physical Society and the American Association for the Advancement of Science.
Michelson's biographers stress, that our hero was not conspicuous by religiousness. His father was a free-thinker and Michelson grew up in non-religious family and have no opportunity to acknowledge the belief of his forebears. He was agnostic through his whole life and only for the short period he was a member of the 21st lodge in Washington.
Morley was deeply religious. His original training had been in theology and he only turned to chemistry, a self-taught hobby, when he was unable to enter the ministry. Michelson, by contrast, was a religious agnostic.
On the religious question, Michelson disagreed with both these men. He had renounced any belief that moral issues were at stake in ...
Antony Hewish (born 11 May 1924) is a British radio astronomer who won the Nobel Prize for Physics in 1974 (together with fellow radio-astronomer Martin Ryle) for his role in the discovery of pulsars. He was also awarded the Eddington Medal of the Royal Astronomical Society in 1969.Comfort A. Adams
Comfort Avery Adams (November 1, 1868 – February 21, 1958) was an American electrical engineer who as a student helped Albert A. Michelson with the Michelson-Morley experiment (1887), which was later viewed as confirming the special relativity theory of Albert Einstein (1905). He was a recipient of the IEEE Edison Medal and AIEE Lamme Medal.Edward W. Morley House
The Edward W. Morley House is a historic house and National Historic Landmark at 26 Westland Avenue in West Hartford, Connecticut. It is notable as the home of the scientist Edward W. Morley (1838-1923) from 1906 to 1923. Morley is famous for his collaboration with Albert A. Michelson on the Michelson-Morley experiment and for his work on the atomic weights of hydrogen and oxygen.Fine structure
In atomic physics, the fine structure describes the splitting of the spectral lines of atoms due to electron spin and relativistic corrections to the non-relativistic Schrödinger equation. It was first measured precisely for the hydrogen atom by Albert A. Michelson and Edward W. Morley in 1887 laying the basis for the theoretical treatment by Arnold Sommerfeld, introducing the fine-structure constant.Fizeau–Foucault apparatus
The Fizeau–Foucault apparatus is either of two types of instrument historically used to measure the speed of light. The conflation of the two instrument types arises in part because Hippolyte Fizeau and Léon Foucault had originally been friends and collaborators. They worked together on such projects as using the Daguerreotype process to take images of the Sun between 1843 and 1845 and characterizing absorption bands in the infrared spectrum of sunlight in 1847.In 1834, Charles Wheatstone developed a method of using a rapidly rotating mirror to study transient phenomena, and applied this method to measure the velocity of electricity in a wire and the duration of an electric spark. He communicated to François Arago the idea that his method could be adapted to a study of the speed of light. Arago expanded upon Wheatstone's concept in an 1838 publication, emphasizing the possibility that a test of the relative speed of light in air versus water could be used to distinguish between the particle and wave theories of light.
In 1845, Arago suggested to Fizeau and Foucault that they attempt to measure the speed of light. Sometime in 1849, however, it appears that the two had a falling out, and they parted ways pursuing separate means of performing this experiment. In 1848−49, Fizeau used, not a rotating mirror, but a toothed wheel apparatus to perform an absolute measurement of the speed of light in air. In 1850, Fizeau and Foucault both used rotating mirror devices to perform relative measures of the speed of light in air versus water. Foucault used a scaled-up version of the rotating mirror apparatus to perform an absolute measurement of the speed of light in 1862. Subsequent experiments performed by Marie Alfred Cornu in 1872–76 and by Albert A. Michelson in 1877–1931 used improved versions of the toothed wheel and rotating mirror experiments to make steadily more accurate estimates of the speed of light.Francis G. Pease
Francis Gladheim Pease (January 14, 1881 – February 7, 1938) was an American astronomer.
He joined the Yerkes Observatory in Wisconsin, where he was an observer and an optician. There he assisted George W. Ritchey who built many of America's first large reflecting telescopes. In 1908 he became an astronomer and instrument maker at the Mount Wilson Observatory. Among his designs was the 100-inch (2,500 mm) telescope at that observatory, and a 50-foot (15 m) interferometer that he used to measure star diameters.
Gene Shoemaker used Pease's high quality photographs of the Moon to make its first geologic map.He was a longtime assistant to Albert A. Michelson. In 1920, Michelson and Pease were able to use the Michelson stellar interferometer fitted to the 100-inch (2,500 mm) telescope at Mt. Wilson to measure the angular diameter of the star Betelgeuse. Their estimate of 0.047" was very close to the value that Eddington had predicted.
He would later be involved in the design of the 200-inch (5,100 mm) Hale Telescope at the Mount Palomar Observatory. In 1928 he made the first discovery of a planetary nebula within a globular cluster, later called Pease 1.
The crater Pease on the Moon is named after him.Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman, Benjamin Franklin, and houses the Benjamin Franklin National Memorial. Founded in 1824, the Franklin Institute is one of the oldest centers of science education and development in the United States.Herbert Friedman
Herbert Friedman (June 21, 1916 – September 9, 2000) was an American pioneer in the application of sounding rockets to solar physics, aeronomy, and astronomy. He was also a statesman and public advocate for science. During his lifetime, he was awarded the Eddington Medal of the Royal Astronomical Society, the National Medal of Science, the Henry Norris Russell Lectureship of the American Astronomical Society, the William Bowie Medal of the American Geophysical Union, the Wolf Foundation Prize in Physics, and the Albert A. Michelson Medal of the Franklin Institute (1972), among others. He was elected a member of the National Academy of Sciences in 1960 and of the American Philosophical Society in 1964.Herbert Walther
Herbert Walther (January 19, 1935 in Ludwigshafen/Rhein, Germany – July 22, 2006 in Munich) was a leader in the fields of quantum optics and laser physics. He was a founding director of the Max Planck Institute of Quantum Optics (MPQ) in Garching, Germany. He also was Chair of Physics at Ludwig Maximilian University of Munich. He is primarily known for his experimental work on cavity quantum electrodynamics (in the form of the micromaser) as well his groundbreaking work on the ion trap. At the time of his death he had over 600 publications and numerous awards from a number of prestigious physics and optics societies. In 1988 he received the Einstein Prize for Laser Science, in 1990 he received the Charles Hard Townes Award, in 1993 the Albert A. Michelson Medal from the Franklin Institute in Philadelphia and in 2003 the Frederic Ives Medal of The Optical Society.Infrared Processing and Analysis Center
The Infrared Processing and Analysis Center (IPAC) provides science operations, data management, data archives and community support for astronomy and planetary science missions. IPAC has a historical emphasis on infrared-submillimeter astronomy and exoplanet science. IPAC has supported NASA, NSF and privately funded projects and missions. It is located on the campus of the California Institute of Technology in Pasadena, California.IPAC was established in 1986 to provide support for the joint European-American orbiting infrared telescope, the Infrared Astronomical Satellite, or IRAS. The IRAS mission performed an unbiased, sensitive all-sky survey at 12, 25, 60 and 100 µm during 1983. After the mission ended, IPAC started the Infrared Science Archive (IRSA) to make the data available to anyone who needed it.
Later, NASA designated IPAC as the U.S. science support center for the European Infrared Space Observatory (ISO), which ceased operations in 1998. About that same time, IPAC was designated as the science center for the Space Infrared Telescope Facility (SIRTF) -- renamed the Spitzer Space Telescope after launch. IPAC also assumed the lead role in various other infrared space missions, including the Wide-field Infrared Explorer (WIRE) and the Midcourse Space Experiment (MSX). IPAC also expanded its support to include ground-based missions with the assumption of science support responsibilities for the Two-Micron All-Sky Survey (2MASS), a near-infrared survey of the entire sky conducted by twin observatories in the Northern and Southern hemispheres.
In 1999, IPAC formed an interferometry science center, originally called the Michelson Science Center (MSC) after interferometry pioneer Albert A. Michelson. MSC was renamed the NASA Exoplanet Science Institute (NExScI) in 2008.
Today, the greater IPAC includes the Spitzer Science Center, the NASA Exoplanet Science Institute and the NASA Herschel Science Center. In 2014, NASA established the Euclid NASA Science Center at IPAC (ENSCI) in order to support US-based investigations using Euclid data. The combined efforts of these centers support more than a dozen science missions and archives. IPAC is also a participating organization in the Virtual Astronomical Observatory (VAO).John S. Millis
Dr. John Schoff Millis (November 22, 1903 – January 1, 1988) was the tenth and last President of Western Reserve College, now Case Western Reserve University.
Millis was born in Palo Alto, California on November 22, 1903. He entered the University of Chicago at the age of 16, earning undergraduate degrees in mathematics and astronomy in 1924. He then received master's degree in physics in 1927 and a doctoral degree in physics in 1931, studying under famed physicist Albert A. Michelson. On June 13, 1929, Millis married Katherine Roseberry Wisner of Baltimore, MD, and together they had three children.
Millis served as dean of Lawrence College in Wisconsin from 1936 to 1941. Millis served as president of the University of Vermont from 1941 to 1949. For the majority of his career, Millis held the position of president of Western Reserve University from 1947 under the federation with Case Institute of Technology in 1967. He served as Chancellor of the new Case Western Reserve University, where he retired on June 30, 1969. While in Cleveland, Millis helped organize the University Circle Development Foundation, predecessor to University Circle Incorporated (UCI). Millis died of cancer at his home in Cleveland Heights, Ohio, on January 1, 1988.Lookout Mountain (Los Angeles County, California)
Lookout Mountain in Los Angeles County, California is a 6,812 foot (2,076 m) peak on the shoulder of Mount San Antonio ("Mount Baldy").
The peak was used by Albert A. Michelson to measure the speed of light in 1925–1929. To do so, a 21.5 mile baseline was established in 1923 by U.S. Coast and Geodetic Survey, with accuracy of 1 part in 11 million, in Pasadena at the base of Mount Baldy, roughly to Rancho Cucamonga at the base of Mount Wilson. It may have been the most accurate baseline ever determined, at the time. Coast and Geodetic Survey then used the baseline to triangulate the distance to the Mount Wilson Observatory, with distance error about 1 part in 5 million, and Michelson measured light travel time between the stations with a rotating mirror apparatus. The concrete piers on Lookout Mountain used for the Michelson observations still exist.The first fire lookout in the Angeles National Forest was built there in 1914 and stood until it burned in 1927.Michelson stellar interferometer
The Michelson stellar interferometer is one of the earliest astronomical interferometers built and used. The interferometer was proposed by Albert A. Michelson in 1890, following a suggestion by Hippolyte Fizeau.
The first such interferometer built was at the Mount Wilson observatory, making use of its 100-inch (~250 centimeters) mirror. It was used to make the first-ever measurement of a stellar diameter, by Michelson and Francis G. Pease, when the diameter of Betelgeuse was measured in December 1920. The diameter was found to be 240 million miles (~380 million kilometers), about the size of the orbit of Mars, or about 300 times larger than the Sun.Michelson–Morley Award
The Michelson–Morley Award is a science award that originated from the Michelson Award that was established in 1963 by the Case Institute of Technology. It was renamed in 1968 by the newly formed Case Western Reserve University (CWRU) after the federation between the Case Institute of Technology and Western Reserve University. The award continued until 1992, and was re-established in 2002. The award in its various forms is named for physics professor Albert A. Michelson (Case School of Applied Sciences) and chemistry professor Edward W. Morley (Western Reserve University) who carried out the famous Michelson–Morley experiment of 1887.Peter P. Sorokin
Peter P. Sorokin (10 July 1931 – 24 September 2015) was an American physicist and co-inventor of the dye laser. He was born in Boston and grew up in Winchester, Massachusetts. He attended Harvard University, receiving a BA degree in 1952 and a PhD in Applied Physics in 1958; his PhD thesis adviser was Nicolaas Bloembergen.Sorokin joined IBM in 1958. Sorokin and his colleague J. R. Lankard, at IBM Research Laboratories, used a ruby laser to excite a near infrared laser dye. Their report was quickly followed by that of F. P. Schäfer. In 1974 Sorokin received the Albert A. Michelson Medal from the Franklin Institute. In 1983 Sorokin was awarded the Comstock Prize in Physics from the National Academy of Sciences and in 1984 the Harvey Prize from Israel's Technion. In 1991 he received the first Arthur L. Schawlow Prize in Laser Science from the American Physical Society. Sorokin is an IBM Fellow since 1968. He was also a Fellow of the Optical Society of America. Toward the end of his career he became interested in astronomy. Sorokin died at the age of 84 on 24 September 2015 from injuries incurred in a fall in August.Roy J. Glauber
Roy Jay Glauber (September 1, 1925 – December 26, 2018) was an American theoretical physicist. He was the Mallinckrodt Professor of Physics at Harvard University and Adjunct Professor of Optical Sciences at the University of Arizona. Born in New York City, he was awarded one half of the 2005 Nobel Prize in Physics "for his contribution to the quantum theory of optical coherence", with the other half shared by John L. Hall and Theodor W. Hänsch. In this work, published in 1963, he created a model for photodetection and explained the fundamental characteristics of different types of light, such as laser light (see coherent state) and light from light bulbs (see blackbody). His theories are widely used in the field of quantum optics.
In statistical physics he pioneered the study of the dynamics of first-order phase transitions, since he first defined and investigated the stochastic dynamics of a Ising model in a largely influential paper published in 1963.
He served on the National Advisory Board of the Center for Arms Control and Non-Proliferation, the research arms of Council for a Livable World.Theodor W. Hänsch
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Hänsch is Director of the Max-Planck-Institut für Quantenoptik (quantum optics) and Professor of experimental physics and laser spectroscopy at the Ludwig-Maximilians University in Munich, Bavaria, Germany.
Hänsch gained his Diplom and doctoral degree from Ruprecht-Karls-Universität Heidelberg in 1960s. Subsequently, he became a professor at Stanford University, California from 1975 to 1986. He was awarded the Comstock Prize in Physics from the National Academy of Sciences in 1983. In 1986, he received the Albert A. Michelson Medal from the Franklin Institute. In the same year Hänsch returned to Germany to head the Max-Planck-Institut für Quantenoptik. In 1989, he received the Gottfried Wilhelm Leibniz Prize of the Deutsche Forschungsgemeinschaft, which is the highest honour awarded in German research. In 2005, he also received the Otto Hahn Award of the City of Frankfurt am Main, the Society of German Chemists and the German Physical Society. In that same year, the Optical Society of America awarded him the Frederic Ives Medal and the status of honorary member in 2008.
One of his students, Carl E. Wieman, received the Nobel Prize in Physics in 2001.
In 1970 he invented a new type of laser which generated light pulses with an extremely high spectral resolution (i.e. all the photons emitted from the laser had nearly the same energy, to a precision of 1 part in a million). Using this device he succeeded to measure the transition frequency of the Balmer line of atomic hydrogen with a much higher precision than before. During the late 1990s, he and his coworkers developed a new method to measure the frequency of laser light to an even higher precision, using a device called the optical frequency comb generator. This invention was then used to measure the Lyman line of atomic hydrogen to an extraordinary precision of 1 part in a hundred trillion. At such a high precision, it became possible to search for possible changes in the fundamental physical constants of the universe over time. For these achievements he became co-recipient of the Nobel Prize in Physics for 2005.William Daniel Phillips
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