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Icaroscope
An icaroscope is a telescope-like nonlinear optical device that enables viewing of both very bright and dark objects in the same image simultaneously. The problem the icaroscope was designed to solve was observing enemy aircraft approaching with the sun behind them, when the bright sun in a clear sky dazzles the observer and masks aircraft near the sun's disc. In the icaroscope, the scene is not viewed directly; instead it is briefly projected onto a screen coated with a special phosphor, and this screen is then shown to the viewer. The specific silver-activated zinc-cadmium sulphide phosphor has a short afterglow even in areas saturated by the full brightness of the sun. By rapidly exposing the phosphor, allowing it to decay for around 5 ms, and showing it to the viewer, the effect is to attenuate the brightness of the sun's disc by about 500 times, allowing details near it to be clearly seen. The icaroscope repeats this process at a rate of 90 Hz, permitting continuous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brian O'Brien (optical Physicist)
Brian O'Brien was an optical physicist and "the founder of the Air Force Studies Board and its chairman for 12 years. O'Brien received numerous awards, including the Medal for Merit, the nation's highest civilian award, for his work on optics in World War II and the Frederic Ives Medal in 1951. Circa 1966 he "chaired an ad hoc committee under the USAF Science Advisory Board (AFSAB) looking into the UFO problem". He also had steering power over National Academy of Sciences (NAS) projects, Project Blue Book, and helped pave the way for the Condon Committee. Early years Brian O' Brien was born in Denver, Colorado in 1898 to Michael Phillip and Lina Prime O' Brien. He attended the Latin School of Chicago from 1909–1915, and continued at the Yale Sheffield scientific school where he earned a Ph.B. in 1918 and a Ph.D. in 1922. He also did course work at Massachusetts Institute of Technology and Harvard University. In 1922 he married Ethel Cornelia Dickerman and they had one son, Bria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Optics
Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in Nonlinearity, nonlinear media, that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typically observed only at very high light intensities (when the electric field of the light is >108 V/m and thus comparable to the atomic electric field of ~1011 V/m) such as those provided by lasers. Above the Schwinger limit, the vacuum itself is expected to become nonlinear. In nonlinear optics, the superposition principle no longer holds. History The first nonlinear optical effect to be predicted was two-photon absorption, by Maria Goeppert Mayer for her PhD in 1931, but it remained an unexplored theoretical curiosity until 1961 and the almost simultaneous observation of two-photon absorption at Bell Labs and the discovery of second-harmonic generation by Peter Franken ''et al.'' at University of Michigan, both shortly after th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun Position (air Combat)
The Sun position in aerial combat is the pilot's ability to position the aircraft relative to the Sun in relationship to the position of the enemy aircraft. The sun position has had different application to different generations of aircraft. During the period when the dogfight dominated air combat, it was used to make visibility and acquisition of own aircraft difficult for the enemy if the Sun was ''behind'' own aircraft. With the introduction of infrared homing air-to-air missiles, the use of the Sun by the pilot was used to confuse the missile guidance system.Shaw, R. (1985) ''Fighter Combat'', p. 59. The advantages of the Sun position were realised early in the history of aerial warfare and is included in the first rule of the ''Dicta Boelcke The ''Dicta Boelcke'' is a list of fundamental aerial maneuvers of aerial combat formulated by First World War German flying ace Oswald Boelcke. Equipped with one of the first fighter aircraft, Boelcke became Germany's foremost flying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphor
A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light, and cathodoluminescent substances which glow when struck by an electron beam ( cathode rays) in a cathode-ray tube. When a phosphor is exposed to radiation, the orbital electrons in its molecules are excited to a higher energy level; when they return to their former level they emit the energy as light of a certain color. Phosphors can be classified into two categories: fluorescent substances which emit the energy immediately and stop glowing when the exciting radiation is turned off, and phosphorescent substances which emit the energy after a delay, so they keep glowing after the radiation is turned off, decaying in brightness over a period of milliseconds to days. Fluorescent materials are used in applications in wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second World War
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Optics
The Institute of Optics is a academic department, department and research center at the University of Rochester in Rochester, New York. The institute grants degrees at the bachelor's degree, bachelor's, master's degree, master's and doctorate, doctoral levels through the University of Rochester College of Arts Sciences and Engineering, University of Rochester School of Engineering and Applied Sciences. Since its founding, the institute has granted over 2,500 degrees in optics, making up about half of the degrees awarded in the field in the United States. The institute is made up of 20 full-time professors, 12 professors with joint appointments in other departments, 10 adjunct professors, 5 research scientists, 11 staff, about 170 undergraduate students and about 110 graduate students. History Founded in 1929, through a grant from Eastman Kodak and Bausch and Lomb, the institute is the oldest Higher education, educational program in the United States devoted to optics. During World ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
