Emil Wolf

Emil Wolf (July 30, 1922 – June 2, 2018)[1] was a Czech-born American physicist who made advancements in physical optics, including diffraction, coherence properties of optical fields, spectroscopy of partially coherent radiation, and the theory of direct scattering and inverse scattering. He was also the author of numerous other contributions to optics.

Emil Wolf
BornJuly 30, 1922
DiedJune 2, 2018 (aged 95)
NationalityCzech, American
CitizenshipUnited States
Alma materBristol University
Known forOptics
Coherence Theory
Wolf effect
AwardsFrederic Ives Medal (1978)
Michelson Medal (1980)
Max Born Award (1987)
Marconi Medal (1987)
Scientific career
InstitutionsUniversity of Edinburgh
University of Manchester
University of Rochester
Doctoral advisorEdward H. Linfoot
Other academic advisorsMax Born
Doctoral studentsGirish Agarwal
M. Suhail Zubairy
Emil Wolf
An example of a signature of Dr. Emil Wolf

Life and career

Wolf was born in Prague, Czechoslovakia. He was forced to leave his native country when the Germans invaded.[2] After brief periods in Italy and France (where he worked for the Czech government in exile), he moved to the United Kingdom in 1940. He received his B.Sc. in Mathematics and Physics (1945), and Ph.D. in Mathematics from Bristol University, England, in 1948. Between 1951 and 1954 he worked at the University of Edinburgh with Max Born, writing the famous textbook on Optics now usually known simply as Born and Wolf. After a period on the Faculty of the University of Manchester, he moved to the United States in 1959 to take a position at the University of Rochester. He became a naturalized U.S. citizen and was the Wilson Professor of Optical Physics at the University of Rochester. He was president of the Optical Society of America in 1978.[3] Until his death Wolf resided in Cloverwood in Pittsford, New York, with his wife.

Wolf predicted a new mechanism that produces redshift and blueshift, that is not due to moving sources (Doppler effect), that has subsequently been confirmed experimentally (called the Wolf effect). Technically, he found that two non-Lambertian sources that emit beamed energy, can interact in a way that causes a shift in the spectral lines. It is analogous to a pair of tuning forks with similar frequencies (pitches), connected together mechanically with a sounding board; there is a strong coupling that results in the resonant frequencies getting "dragged down" in pitch. The Wolf effect can produce either redshifts or blueshifts, depending on the observer's point of view, but is redshifted when the observer is head-on. A subsequent 1999 article by Sisir Roy et al. have suggested that the Wolf effect may explain discordant redshift in certain quasars.[4]

Wolf remained an active teacher, researcher and author well into his 80s. He died on June 2, 2018, aged 95.[2]


Wolf was a very well known book author in the field of optics. Along with Max Born, he co-wrote Principles of Optics[5] one of the standard textbooks of optics commonly known as "Born and Wolf". In addition he co-authored, with Leonard Mandel, Optical Coherence and Quantum Optics.[6] He also authored Introduction to the Theory of Coherence and Polarization of Light and Selected Works of Emil Wolf with Commentary (World Scientific Publishing, 2001, ISBN 981-281-187-7).[7] Furthermore, he edited the Progress in Optics series of books, for Elsevier, from its inception in 1962.

Awards, memberships and degrees



  • Honorary member of the Optical Society of America (President in 1978)
  • Honorary member of the Optical Societies of India and Australia

Honorary degrees

See also


  1. ^ https://www.osa.org/en-us/about_osa/newsroom/obituaries/emil_wolf/
  2. ^ a b Marcotte, Bob (June 4, 2018). "Emil Wolf, pioneer of optical physics, dies at 95". Rochester University. Retrieved June 4, 2018.
  3. ^ "Past Presidents of the Optical Society of America". Optical Society of America.
  4. ^ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000A%26A...353.1134R&db_key=AST&data_type=HTML&format=&high=42ca922c9c04755
  5. ^ Born, Max, and Wolf, Emil (1999). Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light (7th ed.). Cambridge: Cambridge University Press. p. 986. ISBN 9780521642224.CS1 maint: Multiple names: authors list (link)
  6. ^ L. Mandel, and Wolf, Emil (1995). Optical Coherence and Quantum Optics. Cambridge: Cambridge University Press. ISBN 978-0521417112.CS1 maint: Multiple names: authors list (link)
  7. ^ "Selected Works of Emil Wolf with Commentary [eBook]". ebooks.worldscinet.com. Retrieved 14 August 2011.
  8. ^ "Franklin Laureate Database - Albert A. Michelson Medal Laureates". Franklin Institute. Archived from the original on April 6, 2012. Retrieved June 16, 2011.
  9. ^ "Max Born Award". Optical Society. Retrieved August 27, 2011.
  10. ^ "G G Stokes Award". SPIE. Retrieved July 19, 2012.

External links

Aalborg University

Aalborg University (AAU) is a Danish public university with campuses in Aalborg, Esbjerg, and Copenhagen founded in 1974. The university awards bachelor's degrees, master's degrees, and Ph.D. degrees in a wide variety of subjects within humanities, social sciences, information technology, design, engineering, exact sciences, and medicine.

Bernard Richards

Prof. Bernard Richards FBCS, FIMA, FIHRIM, FRAMS is a British computer scientist and an Emeritus Professor of Medical Informatics at the University of Manchester, England.Richards studied mathematics and physics for his bachelor's degree. For his master's degree, he worked under the supervision of Alan Turing (1912–1954) at Manchester as one of Turing's last students, helping to validate Turing’s theory of morphogenesis. Reflecting on Turing's death at the age of 80 during Turing's centenary year in 2012, Richards commented: "The day he died felt like driving through a tunnel and the lights being switched off".After Turing died, Richards changed his research area and worked for his doctorate, studying an aspect of optics, resulting in a Royal Society paper with his supervisor, Professor Emil Wolf. This provided a detailed description of the diffraction of light through a convex lens. After this, Richards moved into the area of medicine, producing an important paper on hormone peaks in the menstrual cycle. Later he worked on expert systems aimed at use in open heart surgery and also intensive care units.

Richards became Professor of Medical Informatics at Manchester University and latterly Emeritus Professor within the School of Computer Science.Richards has been Chairman of the BCS Health Informatics Committee and in 1998 was made BCS Fellow of the Year for Services to Medical Informatics. He was the first President of the Institute for Health Record and Information Management (IHRIM), a member of the International Federation of Records Officers (IFRO). In Europe, he is an Honorary Member of the Ukrainian Association for Computer Medicine of the Ukraine, the Romanian Academy of Medical Science, the John von Neumann Computer Society of Hungary, the Czech Medical Informatics Society, and the Polish Medical Informatics Society. Richards was presented with an award by Queen Elizabeth II for contributing a morphogenesis memento to a time capsule during 2012, Alan Turing's centenary year.


Chromaticity is an objective specification of the quality of a color regardless of its luminance. Chromaticity consists of two independent parameters, often specified as hue (h) and colorfulness (s), where the latter is alternatively called saturation, chroma, intensity, or excitation purity. This number of parameters follows from trichromacy of vision of most humans, which is assumed by most models in color science.

Coherence (physics)

In physics, two wave sources are perfectly coherent if they have a constant phase difference and the same frequency, and the same waveform. Coherence is an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference. It contains several distinct concepts, which are limiting cases that never quite occur in reality but allow an understanding of the physics of waves, and has become a very important concept in quantum physics. More generally, coherence describes all properties of the correlation between physical quantities of a single wave, or between several waves or wave packets.

Interference is the addition, in the mathematical sense, of wave functions. A single wave can interfere with itself, but this is still an addition of two waves (see Young's slits experiment). Constructive or destructive interferences are limit cases, and two waves always interfere, even if the result of the addition is complicated or not remarkable.

When interfering, two waves can add together to create a wave of greater amplitude than either one (constructive interference) or subtract from each other to create a wave of lesser amplitude than either one (destructive interference), depending on their relative phase. Two waves are said to be coherent if they have a constant relative phase. The amount of coherence can readily be measured by the interference visibility, which looks at the size of the interference fringes relative to the input waves (as the phase offset is varied); a precise mathematical definition of the degree of coherence is given by means of correlation functions.

Spatial coherence describes the correlation (or predictable relationship) between waves at different points in space, either lateral or longitudinal. Temporal coherence describes the correlation between waves observed at different moments in time. Both are observed in the Michelson–Morley experiment and Young's interference experiment. Once the fringes are obtained in the Michelson interferometer, when one of the mirrors is moved away gradually, the time for the beam to travel increases and the fringes become dull and finally disappear, showing temporal coherence. Similarly, if in a double-slit experiment, the space between the two slits is increased, the coherence dies gradually and finally the fringes disappear, showing spatial coherence. In both cases, the fringe amplitude slowly disappears, as the path difference increases past the coherence length.

Diffraction-limited system

The resolution of an optical imaging system – a microscope, telescope, or camera – can be limited by factors such as imperfections in the lenses or misalignment. However, there is a principal limit to the resolution of any optical system, due to the physics of diffraction. An optical system with resolution performance at the instrument's theoretical limit is said to be diffraction-limited.The diffraction-limited angular resolution of a telescopic instrument is proportional to the wavelength of the light being observed, and inversely proportional to the diameter of its objective's entrance aperture. For telescopes with circular apertures, the size of the smallest feature in an image that is diffraction limited is the size of the Airy disk. As one decreases the size of the aperture of a telescopic lens, diffraction proportionately increases. At small apertures, such as f/22, most modern lenses are limited only by diffraction and not by aberrations or other imperfections in the construction.

For microscopic instruments, the diffraction-limited spatial resolution is proportional to the light wavelength, and to the numerical aperture of either the objective or the object illumination source, whichever is smaller.

In astronomy, a diffraction-limited observation is one that achieves the resolution of a theoretically ideal objective in the size of instrument used. However, most observations from Earth are seeing-limited due to atmospheric effects. Optical telescopes on the Earth work at a much lower resolution than the diffraction limit because of the distortion introduced by the passage of light through several kilometres of turbulent atmosphere. Some advanced observatories have recently started using adaptive optics technology, resulting in greater image resolution for faint targets, but it is still difficult to reach the diffraction limit using adaptive optics.

Radiotelescopes are frequently diffraction-limited, because the wavelengths they use (from millimeters to meters) are so long that the atmospheric distortion is negligible. Space-based telescopes (such as Hubble, or a number of non-optical telescopes) always work at their diffraction limit, if their design is free of optical aberration.

The beam from a laser with near-ideal beam propagation properties may be described as being diffraction-limited. A diffraction-limited laser beam, passed through diffraction-limited optics, will remain diffraction-limited, and will have a spatial or angular extent essentially equal to the resolution of the optics at the wavelength of the laser.

Esther Hoffman Beller Medal

The Esther Beller Hoffman Medal is an award given by The Optical Society that recognizes outstanding contributions by individuals around the world to the fields of optical science and engineering education. The award was established in 1993 and past winners include optics luminaries such as Emil Wolf, Anthony E. Siegman and Eric Mazur.

Huygens–Fresnel principle

The Huygens–Fresnel principle (named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel) is a method of analysis applied to problems of wave propagation both in the far-field limit and in near-field diffraction.

It states that every point on a wavefront is itself the source of spherical wavelets. The sum of these spherical wavelets forms the wavefront.

Kirchhoff integral theorem

Kirchhoff's integral theorem (sometimes referred to as the Fresnel–Kirchhoff integral theorem) uses Green's identities to derive the solution to the homogeneous wave equation at an arbitrary point P in terms of the values of the solution of the wave equation and its first-order derivative at all points on an arbitrary surface that encloses P.

Leonard Mandel

Leonard Mandel (May 9, 1927 – February 9, 2001) was the Lee DuBridge Professor Emeritus of Physics and Optics at the University of Rochester when he died at the age of 73 at his home in Pittsford, New York. He contributed immensely to theoretical and experimental optics. With Emil Wolf he published the highly regarded book Optical Coherence and Quantum Optics.As written by Jeff Kimble and Emil Wolf in Physics Today; "Mandel is widely credited as being one of the founding fathers of the field of quantum optics. Although he made seminal contributions across most of quantum optics, the central theme of his research was the exploration of the nature of light through insightful theoretical analyses and a set of pioneering experiments that have become landmarks in the field. Not since the beginning of quantum mechanics has an individual so intimately investigated and so dramatically advanced our understanding of the quantum aspects of light." The reader is urged to read a more detailed description of Mandel's work in the full Physics Today obituary at the link referenced below.

Mandel was born in Berlin, Germany, where his father, Robert (Naftali) Mandel, had emigrated from Eastern Europe. He received a BSc degree in mathematics and physics in 1947 and a PhD degree in nuclear physics in 1951 from Birkbeck College, University of London, in the United Kingdom. He became a technical officer at Imperial Chemical Industries Ltd in Welwyn, UK, in 1951. In 1955, he became a lecturer and, later, senior lecturer at Imperial College London, University of London. He remained at Imperial until 1964, when he joined the University of Rochester as a professor of physics. Mandel published over 260 scientific papers dealing with problems of optical coherence, lasers, quantum interactions and non-classical states of light. Together with Prof. Emil Wolf, Mandel organized a series of international conferences, known as the Rochester Conferences on Coherence and Quantum Optics, which were extremely influential in the history of the field of Quantum Optics. Mandel was a referee for approximately 24 scientific journals and 6 research agencies. He was on the Board of Directors of the Optical Society of America from 1985-1988, and was Associate Editor of the Journal of the Optical Society 1970-1976 and 1982-1983. Mandel was also a member of the Editorial Board for both Physical Review and Quantum Optics. In addition to his ground-breaking research, Mandel was known as an exceptional teacher and in 1992 he was awarded the Faculty Graduate Teaching Award by the University of Rochester.

Max Born

Max Born (German: [ˈmaks ˈbɔɐ̯n]; 11 December 1882 – 5 January 1970) was a German-Jewish physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics and supervised the work of a number of notable physicists in the 1920s and 1930s. Born won the 1954 Nobel Prize in Physics for his "fundamental research in quantum mechanics, especially in the statistical interpretation of the wave function".Born entered the University of Göttingen in 1904, where he found the three renowned mathematicians Felix Klein, David Hilbert, and Hermann Minkowski. He wrote his Ph.D. thesis on the subject of "Stability of Elastica in a Plane and Space", winning the University's Philosophy Faculty Prize. In 1905, he began researching special relativity with Minkowski, and subsequently wrote his habilitation thesis on the Thomson model of the atom. A chance meeting with Fritz Haber in Berlin in 1918 led to discussion of the manner in which an ionic compound is formed when a metal reacts with a halogen, which is today known as the Born–Haber cycle.

In the First World War, after originally being placed as a radio operator, he was moved to research duties regarding sound ranging due to his specialist knowledge. In 1921, Born returned to Göttingen, arranging another chair for his long-time friend and colleague James Franck. Under Born, Göttingen became one of the world's foremost centres for physics. In 1925, Born and Werner Heisenberg formulated the matrix mechanics representation of quantum mechanics. The following year, he formulated the now-standard interpretation of the probability density function for ψ*ψ in the Schrödinger equation, for which he was awarded the Nobel Prize in 1954. His influence extended far beyond his own research. Max Delbrück, Siegfried Flügge, Friedrich Hund, Pascual Jordan, Maria Goeppert-Mayer, Lothar Wolfgang Nordheim, Robert Oppenheimer, and Victor Weisskopf all received their Ph.D. degrees under Born at Göttingen, and his assistants included Enrico Fermi, Werner Heisenberg, Gerhard Herzberg, Friedrich Hund, Pascual Jordan, Wolfgang Pauli, Léon Rosenfeld, Edward Teller, and Eugene Wigner.

In January 1933, the Nazi Party came to power in Germany, and Born, who was Jewish, was suspended from his professorship at the University of Göttingen. He emigrated to the United Kingdom, where he took a job at St John's College, Cambridge, and wrote a popular science book, The Restless Universe, as well as Atomic Physics, which soon became a standard textbook. In October 1936, he became the Tait Professor of Natural Philosophy at the University of Edinburgh, where, working with German-born assistants E. Walter Kellermann and Klaus Fuchs, he continued his research into physics. Born became a naturalised British subject on 31 August 1939, one day before World War II broke out in Europe. He remained at Edinburgh until 1952. He retired to Bad Pyrmont, in West Germany, and died in hospital in Göttingen on 5 January 1970.

Max Born Award

The Max Born Award is given by the Optical Society (formerly the Optical Society of America) for "outstanding contributions to physical optics", and is named after Max Born.

OSA Fellow

The OSA Fellow is a membership designation of The Optical Society (OSA) that denotes distinguished scientific accomplishment. The bylaws of this society only allow 10% of its membership to be designated as an OSA Fellow. The OSA Fellow requires peer group nomination.

Pierre-Michel Duffieux

Pierre-Michel Duffieux (1891–1976) was a French physicist, known as the founder of Fourier optics.

Progress in Optics

Progress in Optics are a series of books edited by Emil Wolf published by Elsevier. They consist of collections of already published review articles deemed to be representative of the advances made in the fields of optics.

The series was established in 1962.

The Institute of Optics

The Institute of Optics is a department and research center at the University of Rochester in Rochester, New York. The Institute grants degrees at the bachelor's, master's and doctoral levels through the University of Rochester School of Engineering and Applied Sciences. Since its founding, the Institute has granted over 2,400 degrees in optics, making up about half of the degrees awarded in the field in the U.S. The Institute is made up of 16 full-time professors, 8 professors with joint appointments in other departments, 5 adjunct professors, 12 research scientists, 11 staff, about 100 undergraduate students and about 100 graduate students.According to the National Research Council, in its latest ranking of physics departments, the Institute of Optics was ranked 25th in the nation.

The Optical Society

The Optical Society (originally established as The Optical Society of America, OSA) is a scientific society dedicated to advancing the study of light—optics and photonics—in theory and application, by means of publishing, organizing conferences and exhibitions, partnership with industry, and education. The organization has members in more than 100 countries. As of 2018, the OSA had over 21,000 individual members and more than 265 corporate member companies.


Vacuum is space devoid of matter. The word stems from the Latin adjective vacuus for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is lower than atmospheric pressure. The Latin term in vacuo is used to describe an object that is surrounded by a vacuum.

The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10−12) of atmospheric pressure (100 nPa), and can reach around 100 particles/cm3. Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average in intergalactic space. According to modern understanding, even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, transiting gamma rays, cosmic rays, neutrinos, and other phenomena in quantum physics. In the study of electromagnetism in the 19th century, vacuum was thought to be filled with a medium called aether. In modern particle physics, the vacuum state is considered the ground state of a field.

Vacuum has been a frequent topic of philosophical debate since ancient Greek times, but was not studied empirically until the 17th century. Evangelista Torricelli produced the first laboratory vacuum in 1643, and other experimental techniques were developed as a result of his theories of atmospheric pressure. A torricellian vacuum is created by filling a tall glass container closed at one end with mercury, and then inverting it in a bowl to contain the mercury (see below).Vacuum became a valuable industrial tool in the 20th century with the introduction of incandescent light bulbs and vacuum tubes, and a wide array of vacuum technology has since become available. The recent development of human spaceflight has raised interest in the impact of vacuum on human health, and on life forms in general.

Wolf (name)

Wolf is a name that is used as a surname, given name, and a name among Germanic-speaking peoples: see Wulf.

Names which translate to English "wolf" are also common among many other nations, including many Native American peoples within the current or former extent of the habitat of the gray wolf (essentially all of North America).

Wolf effect

The Wolf effect (sometimes Wolf shift) is a frequency shift in the electromagnetic spectrum.

The phenomenon occurs in several closely related phenomena in radiation physics, with analogous effects occurring in the scattering of light. It was first predicted by Emil Wolf in 1987 and subsequently confirmed in the laboratory in acoustic sources by Mark F. Bocko, David H. Douglass, and Robert S. Knox, and a year later in optic sources by Dean Faklis and George Morris in 1988.

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