query: What effect does a prism have on light?

title: The Black Prism

text: colors of Luxin. Most often than not, this is accomplished by the Prism, a religious leader and political figurehead who rules over the Seven Satrapies as Emperor, although his political power is ceremonial at best. The Prism can draft every color of Luxin, and does not require colored glasses as he possesses the unique ability to split white light into its component colors. Superchromats have extremely acute vision when it come to colors. The inverse of those who are Subchromats (colorblindness), Superchromats can see the minute changes in shades between what most people would assume are the same color. This

title: Prism: Light the Way

text: Prism: Light the Way Prism: Light the Way is a two-dimensional puzzle video game by British company Morpheme Game Studios. In the game, the player, with the help of "Bulboids" that emit light beams, must direct the correct color of light into the "Glowbos". To aid in this objective are a variety of mirrors, T-splitters, filter blocks, and Prisms, collectively called Gluons. The object of the game is to light up all of the Glowbos at the same time with their respective color. The game consists of five different game modes including Puzzle, Time, Hyper, Infinite, and Tutorial. The Puzzle

title: Dispersive prism

text: this case the grating is used in reflection, with light hitting the grating from "inside" the prism before being totally internally reflected back into the prism (and leaving from a different face). The reduction of the light's wavelength inside the prism results in an increase of the resulting spectral resolution by the ratio of the prism's refractive index to that of air. With either a grism or immersed grating, the primary source of spectral dispersion is the grating. Any effect due to chromatic dispersion from the prism itself is incidental, as opposed to actual prism-based spectrometers. An artist's rendition of

title: Prism

text: secondary quality distinction. Newton discussed prism dispersion in great detail in his book "Opticks". He also introduced the use of more than one prism to control dispersion. Newton's description of his experiments on prism dispersion was qualitative. A quantitative description of multiple-prism dispersion was not needed until multiple prism laser beam expanders were introduced in the 1980s. "Dispersive prisms" are used to break up light into its constituent spectral colors because the refractive index depends on frequency; the white light entering the prism is a mixture of different frequencies, each of which gets bent slightly differently. Blue light is slowed

title: Prism

text: Prism In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use "prism" usually refers to this type. Some types of optical prism are not in fact in the shape of geometric prisms. Prisms can be made from any material that is transparent to the wavelengths for which they are designed.

title: Prism

text: incident beam of light makes with the surface, and on the ratio between the refractive indices of the two media (Snell's law). The refractive index of many materials (such as glass) varies with the wavelength or color of the light used, a phenomenon known as "dispersion". This causes light of different colors to be refracted differently and to leave the prism at different angles, creating an effect similar to a rainbow. This can be used to separate a beam of white light into its constituent spectrum of colors. A similar separation happens with iridescent materials, such as a soap bubble.

title: Prism spectrometer

text: Prism spectrometer A prism spectrometer is an optical spectrometer which uses a dispersive prism as its dispersive element. The prism refracts light into its different colors (wavelengths). The dispersion occurs because the angle of refraction is dependent on the refractive index of the prism's material, which in turn is slightly dependent on the wavelength of light that is traveling through it. Light is emitted from a source such as a vapor lamp. A slit selects a thin strip of light which passes through the collimator where it gets parallelized. The aligned light then passes through the prism in which it

title: Prism

text: hyper- or hypotropia. In contrast, spectacles with prisms of equal power for both eyes, called yoked prisms (also: "conjugate prisms", "ambient lenses" or "performance glasses") shift the visual field of both eyes to the same extent. Prism In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use "prism" usually refers

title: Prism spectrometer

text: be used to determine the composition of a material from its emitted spectral lines. A prism spectrometer may be used to measure the refractive index of a material if the wavelengths of the light used are known. The calibration of a prism spectrometer is carried out with known spectral lines from vapor lamps or laser light. Prism spectrometer A prism spectrometer is an optical spectrometer which uses a dispersive prism as its dispersive element. The prism refracts light into its different colors (wavelengths). The dispersion occurs because the angle of refraction is dependent on the refractive index of the prism's

title: Abbe prism

text: Abbe prism In optics, an Abbe prism, named for its inventor, the German physicist Ernst Abbe, is a type of "constant deviation dispersive prism" similar to a Pellin–Broca prism. The prism consists of a block of glass forming a right prism with 30°–60°–90° triangular faces. When in use, a beam of light enters face AB, is refracted and undergoes total internal reflection from face BC, and is refracted again on exiting face AC. The prism is designed such that one particular wavelength of the light exits the prism at a deviation angle (relative to the light's original path) of exactly

title: Wedge prism

text: Wedge prism The wedge prism is a prism with a shallow angle between its input and output surfaces. This angle is usually 3 degrees or less. Refraction at the surfaces causes the prism to deflect light by a fixed angle. When viewing a scene through such a prism, objects will appear to be offset by an amount that varies with their distance from the prism. For a wedge prism in air, rays of light passing through the prism are deflected by the angle δ, which is approximately given by where "n" is the index of refraction of the prism material,

title: Pellin–Broca prism

text: Pellin–Broca prism A Pellin–Broca prism is a type of constant-deviation dispersive prism similar to an Abbe prism. The prism is named for its inventors, the French instrument maker Ph. Pellin and professor of physiological optics André Broca. The prism consists of a four-sided block of glass shaped as a right prism with 90°, 75°, 135°, and 60° angles on the end faces. Light enters the prism through face AB, undergoes total internal reflection from face BC, and exits through face AD. The refraction of the light as it enters and exits the prism is such that one particular wavelength of

title: Wollaston prism

text: Wollaston prism A Wollaston prism is an optical device, invented by William Hyde Wollaston, that manipulates polarized light. It separates light into two separate linearly polarized outgoing beams with orthogonal polarization. The two beams will be polarized according to the optical axis of the two right angle prisms. The Wollaston prism consists of two orthogonal prisms of birefringent material—typically a uniaxial material such as calcite. These prisms are cemented together on their base (traditionally with Canada balsam) to form two right triangle prisms with perpendicular optic axes. Outgoing light beams diverge from the prism as ordinary and extraordinary rays due

title: Amici prism

text: Amici prism An Amici prism, named for the astronomer Giovanni Amici, is a type of compound dispersive prism used in spectrometers. The Amici prism consists of two triangular prisms in contact, with the first typically being made from a medium-dispersion crown glass, and the second a higher-dispersion flint glass. Light entering the first prism is refracted at the first air-glass interface, refracted again at the interface between the two prisms, and then exits the second prism at near-normal incidence. The prism angles and materials are chosen such that one wavelength (colour) of light, the "centre wavelength", exits the prism parallel

title: Pellin–Broca prism

text: are also commonly used in optical atomic spectroscopy. Pellin–Broca prism A Pellin–Broca prism is a type of constant-deviation dispersive prism similar to an Abbe prism. The prism is named for its inventors, the French instrument maker Ph. Pellin and professor of physiological optics André Broca. The prism consists of a four-sided block of glass shaped as a right prism with 90°, 75°, 135°, and 60° angles on the end faces. Light enters the prism through face AB, undergoes total internal reflection from face BC, and exits through face AD. The refraction of the light as it enters and exits the

title: Dichroic prism

text: Dichroic prism A dichroic prism is a prism that splits light into two beams of differing wavelength (colour). A trichroic prism assembly combines two dichroic prisms to split an image into 3 colours, typically as red, green and blue of the RGB colour model. They are usually constructed of one or more glass prisms with dichroic optical coatings that selectively reflect or transmit light depending on the light's wavelength. That is, certain surfaces within the prism act as dichroic filters. These are used as beam splitters in many optical instruments. (See: Dichroism, for the etymology of the term.) One common

title: Deck prism

text: Deck prism A deck prism is a prism inserted into the deck of a ship to provide light down below. For centuries, sailing ships used deck prisms to provide a safe source of natural sunlight to illuminate areas below decks. Before electricity, light below a vessel's deck was provided by candles, oil and kerosene lamps—all dangerous aboard a wooden ship. The deck prism was a clever solution: laid flush into the deck, the glass prism refracted and dispersed natural light into the space below from a small deck opening without weakening the planks or becoming a fire hazard. In normal

title: Prism compressor

text: 1984 by Fork et al. Additional experimental developments include a prism-pair pulse compressor and a six-prism pulse compressor for semiconductor lasers. The multiple-prism dispersion theory, for pulse compression, was introduced in 1982 by Duarte and Piper, extended to second derivatives in 1987, and further extended to higher order phase derivatives in 2009. An additional compressor, using a large prism with lateral reflectors to enable a multi-pass arrangement at the prism, was introduced in 2006. Almost all optical materials that are transparent for visible light have a "normal", or positive, dispersion: the refractive index decreases with increasing wavelength. This means that

title: Prism

text: so for a thin prism the deviation angle varies with wavelength according to René Descartes had seen light separated into the colors of the rainbow by glass or water, though the source of the color was unknown. Isaac Newton's 1666 experiment of bending white light through a prism demonstrated that all the colors already existed in the light, with different color "corpuscles" fanning out and traveling with different speeds through the prism. It was only later that Young and Fresnel combined Newton's particle theory with Huygens' wave theory to explain how color arises from the spectrum of light. Newton arrived

title: Geometrical optics

text: example, the propagation of light through a prism results in the light ray being deflected depending on the shape and orientation of the prism. Additionally, since different frequencies of light have slightly different indexes of refraction in most materials, refraction can be used to produce dispersion spectra that appear as rainbows. The discovery of this phenomenon when passing light through a prism is famously attributed to Isaac Newton. Some media have an index of refraction which varies gradually with position and, thus, light rays curve through the medium rather than travel in straight lines. This effect is what is responsible

title: Prism spectrometer

text: is refracted twice (once when entering and once when leaving). Due to the nature of a dispersive element the angle with which light is refracted depends on its wavelength. This leads to a spectrum of thin lines of light, each being observable at a different angle. Replacing the prism with a diffraction grating would result in a grating spectrometer. Optical gratings are less expensive, provide much higher resolution, and are easier to calibrate, due to their linear diffraction dependency. A prism's refraction angle varies nonlinearly with wavelength. On the other hand, gratings have significant intensity losses. A prism spectrometer may

title: Prism

text: at his conclusion by passing the red color from one prism through a second prism and found the color unchanged. From this, he concluded that the colors must already be present in the incoming light — thus, the prism did not create colors, but merely separated colors that are already there. He also used a lens and a second prism to recompose the spectrum back into white light. This experiment has become a classic example of the methodology introduced during the scientific revolution. The results of the experiment dramatically transformed the field of metaphysics, leading to John Locke's primary vs

title: Prism coupler

text: at an angle formula_7 normal from the waveguide surface. where formula_9 is the index of refraction of the prism. where formula_11 is the index of air (~1) and formula_6 is the propagation constant of the waveguide. In order to have a guided mode, formula_13. This would imply that formula_14, which is not possible. Prism coupler A prism coupler is a prism designed to couple a substantial fraction of the power contained in a beam of light (e.g., a laser beam) into a thin film to be used as a waveguide without the need for precision polishing of the edge of

title: Prism

text: Typical materials include glass, plastic, and fluorite. A dispersive prism can be used to break light up into its constituent spectral colors (the colors of the rainbow). Furthermore, prisms can be used to reflect light, or to split light into components with different polarizations. Light changes speed as it moves from one medium to another (for example, from air into the glass of the prism). This speed change causes the light to be refracted and to enter the new medium at a different angle (Huygens principle). The degree of bending of the light's path depends on the angle that the

title: Prism coupler

text: of partially containing the guided wave over the coupling distance. The thin film at the bottom of the prism is referred to as the "tunneling layer". The tunneling layer must have a lower refractive index than the waveguide film and may actually be implemented as a layer of air. The thickness of the tunneling layer will be on the order of a fraction of a wavelength (tens to hundreds of nanometers for visible light). The prism and tunneling layer are pressed against the waveguide film. The beam enters the front face of the prism and strikes the tunneling layer somewhat

title: Glan–Taylor prism

text: Glan–Taylor prism A Glan–Taylor prism is a type of prism which is used as a polarizer or polarizing beam splitter. It is one of the most common types of modern polarizing prism. It was first described by Archard and Taylor in 1948. The prism is made of two right-angled prisms of calcite (or sometimes other birefringent materials) separated on their long faces with an air gap. The optical axes of the calcite crystals are aligned parallel to the plane of reflection. Total internal reflection of "s"-polarized light at the air gap ensures that only "p"-polarized light is transmitted by the

title: Wedge prism

text: target is carefully calibrated to the desired plot size, and the plot is defined as all the area in which the target is "in" as viewed through the prism. Wedge prism The wedge prism is a prism with a shallow angle between its input and output surfaces. This angle is usually 3 degrees or less. Refraction at the surfaces causes the prism to deflect light by a fixed angle. When viewing a scene through such a prism, objects will appear to be offset by an amount that varies with their distance from the prism. For a wedge prism in air,

title: Wollaston prism

text: to the differences in the indexes of refraction, with the angle of divergence determined by the prisms' wedge angle and the wavelength of the light. Commercial prisms are available with divergence angles from less than 1° to about 45°. Wollaston prism A Wollaston prism is an optical device, invented by William Hyde Wollaston, that manipulates polarized light. It separates light into two separate linearly polarized outgoing beams with orthogonal polarization. The two beams will be polarized according to the optical axis of the two right angle prisms. The Wollaston prism consists of two orthogonal prisms of birefringent material—typically a uniaxial

title: Prism correction

text: displacement at 100 cm, or 1 meter. This can be represented mathematically as: where formula_2 is the amount of prism correction in prism dioptres, and formula_3 is the angle of deviation of the light. For a prism with apex angle formula_4 and refractive index formula_5, Prentice's rule, named so after the optician Charles F. Prentice, is a formula used to determine the amount of induced prism in a lens: where: The primary use of Prentice's rule is that under certain circumstances, the prescribed prism can be obtained without grinding prism into the lenses, by decentering the lenses as worn by

title: Wedge prism

text: accurate as other angle gauges when properly calibrated and used properly. One simply holds the prism directly over the plot center, and by focusing on a tree, the refracted light will offset the trunk of the tree. The wedge prism is used to take measurements in both land management and in timber procurement. Other tools often used to accompany the wedge prism in taking forest inventory are clinometers, Biltmore sticks, relascopes, and Diameter Tapes. A wedge prism can also be used with a target placed at plot center, to establish fixed radius plots. In this function, the size of the

title: Pellin–Broca prism

text: the light is deviated by exactly 90°. As the prism is rotated around an axis O, the line of intersection of bisector of ∠BAD and the reflecting face BC, the selected wavelength which is deviated by 90° is changed without changing the geometry or relative positions of the input and output beams. The prism is commonly used to separate a single required wavelength from a light beam containing multiple wavelengths, such as a particular output line from a multi-line laser due to its ability to separate beams even after they have undergone a non-linear frequency conversion. For this reason, they

title: Compound prism

text: Compound prism A compound prism is a set of multiple triangular prism elements placed in contact, and often cemented together to form a solid assembly. The use of multiple elements gives several advantages to an optical designer: The simplest compound prism is a doublet, consisting of two elements in contact, as shown in the figure at right. A ray of light passing through the prism is refracted at the first air-glass interface, again at the interface between the two glasses, and a final time at the exiting glass-air interface. The deviation angle formula_2 of the ray is given by the

title: Prism lighting

text: reflect light hitting their top surfaces upwards. Refraction is minimized, to avoid colouring the light. The reflection-based films are more transparent (both are translucent), but they tend to send the light up at the ceiling, not deeper into the room. Refraction-based films are translucent rather than transparent, but offer finer control over the direction of the outgoing light beam; the film can be made in a variety of prism shapes to refract light by a variety of angles. Older glass elements were cast, and might be cut and polished. Prism tiles were often made of single prisms joined with zinc,

title: Prism lighting

text: was to send the available light across the room nearly horizontally. One company sold tiles with nine prescriptions, giving different angles of refraction. Different prescriptions were often used in different parts of the same window transom, sometimes to disperse the light vertically, and sometimes to bend light horizontally around obstacles like pillars. Prisms tiles sometimes has elaborate artistic designs moulded into the outside; Frank Lloyd Wright famously created over forty prism tile designs. Prism lighting works more effectively in light, open spaces. Some believe that it contributed to the trend away from dark, subdivided Victorian interiors to open-plan, light-coloured ones.

title: Dispersive prism

text: prism led Sir Isaac Newton to conclude that light consisted of a mixture of different colors, which when combined could appear "white." Although the refractive index is dependent on the wavelength in every material, some materials have a much more powerful wavelength dependence (are much more dispersive) than others. Crown glasses such as BK7 have a relatively small dispersion, while flint glasses have a much stronger dispersion (for visible light) and hence are more suitable for use as dispersive prisms. Fused quartz and other optical materials are used at ultraviolet and infrared wavelengths where normal glasses become opaque. The top

title: Dichroic prism

text: of prism A and exits it through a side face. The remainder of the beam enters the second prism (B) and is split by a second filter coating (F) which reflects red light but transmits shorter wavelengths. The red beam is also totally internally reflected due to a small air-gap between prisms A and B. The remaining green component of the beam travels through prism C. The trichroic prism assembly can be used in reverse to combine red, green and blue beams into a coloured image, and is used in this way in some projector devices. Assemblies with more than

title: Glan–Thompson prism

text: Glan–Thompson prism A Glan–Thompson prism is a type of polarizing prism similar to the Nicol and Glan–Foucault prisms. A Glan–Thompson prism consists of two right-angled calcite prisms that are cemented together by their long faces. The optical axes of the calcite crystals are parallel and aligned perpendicular to the plane of reflection. Birefringence splits light entering the prism into two rays, experiencing different refractive indices; the "p"-polarized ordinary ray is totally internally reflected from the calcite–cement interface, leaving the "s"-polarized extraordinary ray to be transmitted. The prism can therefore be used as a polarizing beam splitter. Traditionally Canada balsam was

title: Dove prism

text: Refraction at the entrance and exit surfaces results in substantial image astigmatism when used in convergent light. Thus the Dove prism is used almost exclusively for images appearing at infinity. If the flat hypoteneuse surface of a Dove prism is cut into a roof shape, the result is an Amici roof prism. A reflection in one axis of a plane is always equivalent to a reflection and rotation in two other axes (with the angle between the source and image being twice the angle between the source and reflection axis of the prism). Thus, Dove prisms can be used to

title: Nicol prism

text: interface. It passes out the top side of the upper half of the prism with some refraction, as shown. The "extraordinary" ray, or "e"-ray, experiences a lower refractive index ("n" = 1.486) in the calcite and is not totally reflected at the interface because it strikes the interface at a sub-critical angle. The "e"-ray merely undergoes a slight refraction, or bending, as it passes through the interface into the lower half of the prism. It finally leaves the prism as a ray of plane-polarized light, undergoing another refraction, as it exits the far right side of the prism. The two

title: Dichroic prism

text: 3 beams are possible. When used for color separation, in an imaging system, this method has some advantages over other methods, such as the use of a Bayer filter. Most of those characteristics derive from the usage of dichroic filters and are in common with those. The advantages include: Dichroic prism A dichroic prism is a prism that splits light into two beams of differing wavelength (colour). A trichroic prism assembly combines two dichroic prisms to split an image into 3 colours, typically as red, green and blue of the RGB colour model. They are usually constructed of one or

title: Prism compressor

text: the compressor can be both negative around refractive index "n" = 1.6 (red curve) and positive (blue curve). The range with a negative dispersion is relatively short since prism P2 can only be moved upwards over a short distance before the light ray misses it altogether. In principle, the α angle can be varied to tune the dispersion properties of a prism compressor. In practice, however, the geometry is chosen such that the incident and refracted beam have the same angle at the central wavelength of the spectrum to be compressed. This configuration is known as the "angle of minimum

title: Dichroic prism

text: application of dichroic prisms is in some camcorders and high-quality digital cameras. A "trichroic prism assembly" is a combination of two dichroic prisms which are used to split an image into red, green, and blue components, which can be separately detected on three CCD arrays. A possible layout for the device is shown in the diagram. A light beam enters the first prism (A), and the blue component of the beam is reflected from a low-pass filter coating (F) that reflects blue light (high-frequency), but transmits longer wavelengths (lower frequencies). The blue beam undergoes total internal reflection from the front

title: Prism correction

text: of each eye. Individuals with nystagmus, Duane's retraction syndrome, 4th Nerve Palsy, and other eye movement disorders experience an improvement in their symptoms when they turn or tilt their head. Yoked prism can move the image away from primary gaze without the need for a constant head tilt or turn. Prism correction is measured in prism dioptres. A prescription that specifies prism correction will also specify the "base". The base is the thickest part of the lens and is opposite from the apex. Light will be bent towards the base and the image will be shifted towards the apex. In

title: Wedge prism

text: were sometimes used in rangefinding, by combining the image formed by one telescope with the image formed by another. The wedge prism is primarily used in a similar manner as an angle gauge in variable-radius plot sampling. In this type of sampling, the wedge prism is used to estimate basal area of a group of trees by counting trees which are "in" or "out" of a plot centered on a single point. Because the wedge prism refracts light to offset the object of interest (e.g. a tree), it can be used to determine whether or not the tree should be

title: Dispersive prism

text: prism's material (often, but not always, a glass) index of refraction varying with wavelength. By application of Snell's law, one can see that as the wavelength changes, and the refractive index changes, the deflection angle of a light beam will change, separating the colors (wavelength components) of the light spatially. Generally, longer wavelengths (red) thereby undergo a smaller deviation than shorter wavelengths (blue) where the refractive index is larger. A good mathematical description of single-prism dispersion is given by Born and Wolf. The case of multiple-prism dispersion is treated by Duarte. The dispersion of white light into colors by a

title: Prism coupler

text: a thin film. The film lies on a substrate such as a glass microscope slide and might have a thickness of the order of the wavelength of the incident light (0.550 μm for green light). The refractive index of the film is made greater than that of the glass slide, the film can serve as a dielectric planar waveguide for light via total internal reflection off the film–glass interface (and film–air interface). The prism coupler consists of a near cube of high–refractive-index glass and a second thin film at the bottom that contacts the waveguide film and serves the function

title: Abbe–Koenig prism

text: the prism. The light is then reflected from the opposite 30° face and exits, again at normal incidence. The net effect of the internal reflections is to flip the image both vertically and horizontally. This produces a 180° image rotation (without changing the image's handedness) and allows use of the prism as an "image erecting system". Unlike the more common double Porro prism configuration, the Abbe–Koenig prism does not displace the output beam from the input beam, making it advantageous in some instruments. The prism is also less bulky than the double Porro design. The prism is sometimes simply called

title: Prism lighting

text: Prism lighting Prism lighting is the use of prisms to improve the distribution of light in a space. It is usually used to distribute daylight, and is a form of anidolic lighting. Prism lighting was popular from its introduction in the 1890s through to the 1930s, when cheap electric lights were commonplace and prism lighting became unfashionable. While mass production of prism lighting systems ended around 1940, the 2010s have seen a revival using new materials. The human eye's response to light is non-linear: halving the light level does not halve the perceived brightness of a space, it makes it

title: Prism: Light the Way

text: game mode has 15 levels of 8 stages each totaling 120 puzzles altogether. There is also a scoreboard that keeps track of your best times for each puzzle. The various Gluons are there to aid you in redirecting the light from the Bulboids into the Glowbos positioned in various places on each puzzle: Prism: Light the Way Prism: Light the Way is a two-dimensional puzzle video game by British company Morpheme Game Studios. In the game, the player, with the help of "Bulboids" that emit light beams, must direct the correct color of light into the "Glowbos". To aid in

title: Porro prism

text: is rotated by 180° and exits in the opposite direction offset from its entrance point. Since the image is reflected twice, the handedness of the image is unchanged. Porro prisms are most often used in pairs, forming a double Porro prism. A second prism, rotated 90° with respect to the first, is placed such that light will traverse both prisms. The net effect of the prism system is a beam parallel to but displaced from its original direction, with the image rotated 180°. As before, the handedness of the image is unchanged. Double Porro prism systems are used in small

title: Prism adaptation

text: during prism exposure (Newport and Schnek, 2012). The negative after-effect is not permanent but varies in its duration depending on the number of sessions and time the patient is exposed to prism adaptation sessions. Eventually the after-effect wears off and pointing abilities return to pre-test levels. Different regions of the brain are activated throughout the duration of prism exposure and have proven to contribute to the error reductions in pointing to a visual target. An fMRI study done in 2009 by Laute et al. examined the neural activation patterns associated with the error correction phase of prism adaptation and found

title: Prism adaptation

text: The direct effect adaptation observed as a result of prism exposure persists and results in what is known as the prism adaptation negative after-effect. The negative after-effect causes the initial attempts in pointing to the visual target during the post-test to be in the direction opposite that of the visual shift. For example, if the observer was exposed to rightward shifting prisms, then the initial pointing errors induced by the after-effect would be to the left of the target. The extent of the observed after-effects reflects the amount of realignment that has taken place in visual and proprioceptive spatial maps

title: Prism

text: Prisms will generally disperse light over a much larger frequency bandwidth than diffraction gratings, making them useful for broad-spectrum spectroscopy. Furthermore, prisms do not suffer from complications arising from overlapping spectral orders, which all gratings have. Prisms are sometimes used for the internal reflection at the surfaces rather than for dispersion. If light inside the prism hits one of the surfaces at a sufficiently steep angle, total internal reflection occurs and "all" of the light is reflected. This makes a prism a useful substitute for a mirror in some situations. Ray angle deviation and dispersion through a prism can be

title: Wedge prism

text: prism must be roughly parallel to the ground in order to provide an accurate estimate on sloped ground. Wedge prisms can be difficult to use in wet conditions due to the effect water droplets have on the optical properties of the glass. Wedge prisms come in different colors such as clear or amber. The amber provides the same function as the clear wedge prism, only it reduces glare and is easier to use on overcast or cloudy days. Operating a wedge prism is one technique used in forestry today because the wedge prism is simple, relatively inexpensive, portable, and as

title: Roof prism

text: diffraction from the discontinuity at the roof crest. The unwanted interference effects are suppressed by vapour-depositing a special dielectric coating known as a phase-compensating coating on the roof surfaces of the roof prism. This coating corrects for the difference in geometric phase between s- and p-polarized light so both have effectively the same phase shift, preventing image-degrading interference. Roof prism A roof prism (also called a Dach prism or Dachkanten prism, from the German: "Dachkante", lit. "roof edge") is a reflective optical prism containing a section where two faces meet at a 90° angle. These two 90° faces resemble the

title: Dispersive prism

text: Dispersive prism In optics, a dispersive prism is an optical prism, usually having the shape of a geometrical triangular prism, used as a spectroscopic component. Spectral dispersion is the best known property of optical prisms, although not the most frequent purpose of using optical prisms in practice. Triangular prisms are used to disperse light, that is, to break light up into its spectral components (the colors of the rainbow). Different wavelengths (colors) of light will be deflected by the prism at different angles, producing a spectrum on a detector (or seen through an eyepiece). This is a result of the

title: Porro prism

text: a distance of at least one beam diameter. A variation on the double Porro prism is the Porro-Abbe prism. Porro prism In optics, a Porro prism, named for its inventor Ignazio Porro, is a type of "reflection prism" used in optical instruments to alter the orientation of an image. It consists of a block of glass shaped as a right geometric prism with right-angled triangular end faces. In operation, light enters the large rectangular face of the prism, undergoes total internal reflection twice from the sloped faces, and exits again through the large rectangular face. Because the light exits and

title: Dove prism

text: create "beam rotators", which have applications in fields such as interferometry, astronomy, and pattern recognition. Lesso and Padgett (1999) and Moreno et al. (2003, 2004) found that there is a change in the state of polarization of a beam of light on passing through a rotated dove prism. Polarization rotation in the infrared has been known for much longer. (Johnston 1977) The polarization-transforming properties of dove prisms are of particular interest because they can influence the signal measurement of the scientific instrument. Dove prism A Dove prism is a type of reflective prism which is used to invert an image.

title: Deck prism

text: collected by the prism and be made visible on the deck even in daylight. The names "deck light", "dead light" or "deadlight" are sometimes used, though the latter is uncommon as a reference to prisms, as more often refers to non-opening plain-glass panels. Deadlights were commonplace for lighting underground vaults in the 19th century, in which application they were also called "pavement lights" (UK) or "vault lights" (US). Deck prism A deck prism is a prism inserted into the deck of a ship to provide light down below. For centuries, sailing ships used deck prisms to provide a safe source

title: Prism graph

text: "r", "r", and "f") as its generators. The "n"-gonal prism graphs with odd values of "n" may be constructed as circulant graphs formula_2. However, this construction does not work for even values of "n". The graph of an "n"-gonal prism has 2"n" vertices and 3"n" edges. They are regular, cubic graphs. Since the prism has symmetries taking each vertex to each other vertex, the prism graphs are vertex-transitive graphs. As polyhedral graphs, they are also 3-vertex-connected planar graphs. Every prism graph has a Hamiltonian cycle. Among all biconnected cubic graphs, the prism graphs have within a constant factor of the

title: Prism lighting

text: specified angle, ideally sending it nearly horizontally into the room. Redirecting films can be used as a substitute for opaque blinds. Prism lighting Prism lighting is the use of prisms to improve the distribution of light in a space. It is usually used to distribute daylight, and is a form of anidolic lighting. Prism lighting was popular from its introduction in the 1890s through to the 1930s, when cheap electric lights were commonplace and prism lighting became unfashionable. While mass production of prism lighting systems ended around 1940, the 2010s have seen a revival using new materials. The human eye's

title: Porro prism

text: Porro prism In optics, a Porro prism, named for its inventor Ignazio Porro, is a type of "reflection prism" used in optical instruments to alter the orientation of an image. It consists of a block of glass shaped as a right geometric prism with right-angled triangular end faces. In operation, light enters the large rectangular face of the prism, undergoes total internal reflection twice from the sloped faces, and exits again through the large rectangular face. Because the light exits and enters the glass only at normal incidence, the prism is not dispersive. An image travelling through a Porro prism

title: Prism adaptation

text: brain and results in improved higher order visual spatial representations that allow for the sustained improvement of unilateral neglect symptoms (Serino et al., 2006). The positive effects of prism adaptation on symptoms of neglect have been shown to vary in the amount of time they persist and in their generalization to other sensory modality tasks besides visual-motor tasks. The short term (2-hour) amelioration of unilateral neglect introduced by Rosetti et al., 1998 sparked an interest in converting this short-term effect into a long-term rehabilitative effect. The following is the progression of scientific studies conducted to investigate prism adaptation's potential rehabilitative

title: Roof prism

text: the s-polarized and p-polarized light results in a different intensity distribution perpendicular to the roof edge as compared to that along the roof edge. This effect reduces contrast and resolution in the image perpendicular to the roof edge, producing an inferior image compared to that from a porro prism erecting system. This roof edge diffraction effect may also be seen as a diffraction spike perpendicular to the roof edge generated by bright points in the image. This effect can be seen in the elongation of the Airy disk in the direction perpendicular crest of the roof as this is a

title: Prism coupler

text: Prism coupler A prism coupler is a prism designed to couple a substantial fraction of the power contained in a beam of light (e.g., a laser beam) into a thin film to be used as a waveguide without the need for precision polishing of the edge of the film, without the need for sub-micrometer alignment precision of the beam and the edge of the film, and without the need for matching the numerical aperture of the beam to the film. Using a prism coupler, a beam coupled into a thin film can have a diameter hundreds of times the thickness

title: Bauernfeind prism

text: Bauernfeind prism A Bauernfeind prism is a type of reflecting prism used to deviate a beam of light by 45° to 60°, depending on its construction, while neither flipping nor rotating the image. It is named for its inventor, the German expert of geodesy . The beam is reflected twice in the prism, with one reflection happening at less than the critical angle, therefore the prism requires a reflective coating for this surface to be usable in practice. A Bauernfeind prism with 45° beam deviation is also known as a half-penta prism or semipentaprism. A Bauernfeind prism is used together

title: Does exactly what it says on the tin

text: began a similar copycat advertising campaign in Ireland stating that its product "does exactly what it says on the tube". The phrase is a registered trademark of the Sherwin-Williams Company, the owner of Ronseal, across the European Community for products including paints, varnishes, and wood preservatives (E3085826). In 2007, a song titled "What It Says on the Tin" was released by the British singer Katie Melua. Although the song is about relationships, the phrase has a similar meaning. Does exactly what it says on the tin "It does exactly what it says on the tin" was originally an advertising slogan

title: PRISM (TV network)

text: Avenue in South Philadelphia. Snider convinced the Philadelphia 76ers and Philadelphia Phillies to allow the channel to televise their home games, after the two teams expressed concern that broadcasting games would hurt attendance; the teams' concerns subsided when they discovered PRISM broadcasts had no effect on the number of spectators who attended their respective games at The Spectrum and Veterans Stadium and helped them earn additional revenue from carrying the home game telecasts. What differentiated PRISM from other subscription television services – some of which included ONTV, SelecTV and Z Channel, and to some extent, national services such as HBO

title: Dispersive prism

text: a dispersive prism is seen on the cover of Pink Floyd's "The Dark Side of the Moon", one of the best-selling albums of all time. The iconic graphic shows a coherent ray of white light entering the prism and beginning to disperse, and shows the spectrum leaving the prism. Dispersive prism In optics, a dispersive prism is an optical prism, usually having the shape of a geometrical triangular prism, used as a spectroscopic component. Spectral dispersion is the best known property of optical prisms, although not the most frequent purpose of using optical prisms in practice. Triangular prisms are used

title: Amici prism

text: to (but offset from) the entrance beam. The prism assembly is thus a "direct-vision prism", and is commonly used as such in hand-held spectroscopes. Other wavelengths are deflected at angles depending on the glass dispersion of the materials. Looking at a light source through the prism thus shows the optical spectrum of the source. By 1860, Amici realized that one can join this type of prism back-to-back with a reflected copy of itself, producing a three-prism arrangement known as a double Amici prism. This doubling of the original prism increases the angular dispersion of the assembly, and also has the

title: Glan–Foucault prism

text: Glan–Foucault prism A Glan–Foucault prism (also called a Glan–air prism) is a type of prism which is used as a polarizer. It is similar in construction to a Glan–Thompson prism, except that two right-angled calcite prisms are spaced with an air gap instead of being cemented together. Total internal reflection of "p"-polarized light at the air gap means that only "s"-polarized light is transmitted straight through the prism. Compared to the Glan–Thompson prism, the Glan–Foucault has a narrower acceptance angle over which it works, but because it uses an air gap rather than cement, much higher irradiances can be used

title: Porro–Abbe prism

text: beam. The image is rotated 180° in the process, and for this reason the prism is used as an "image erection system" in some binoculars, and camera viewfinders. The prism is not dispersive since light enters and exits the prism only at normal incidence. Since the light is reflected an even number of times, the image's handedness is not changed. For ease of manufacture, the prism is often made as a pair of double-right-angled prisms and the two halves cemented together. A single half of the assembly is sometimes also called a Porro–Abbe prism. Porro–Abbe prism A Porro–Abbe prism (sometimes

title: The Fox (What Does the Fox Say?)

text: neighborhood in Edwards Landing, Leesburg, Virginia, who every Halloween creates an LED light show with a hit song. This song appears in "Just Dance 2015". This song for Leicester City title song parody "What do the Foxes Say?" in 442oons video. !scope="col" colspan="3"| Streaming Note: The Fox (What Does the Fox Say?) "The Fox (What Does the Fox Say?)" is an electronic dance novelty song and viral video by Norwegian comedy duo Ylvis. The top trending video of 2013 on YouTube, "The Fox" was posted on the video-sharing website on 3 September 2013, and has received over 800 million views

title: Bauernfeind prism

text: with a Schmidt roof prism to form a Schmidt–Pechan prism. The Bauernfeind prism is commonly used in microscope tubes and in geodesy to deviate the path to the eyepiece in order make the device more ergonomic. More recent applications are glasses that deflect the viewing angle either downwards (for relaxed reading or watching TV), or upwards (for watching a climber while belaying). Bauernfeind prism A Bauernfeind prism is a type of reflecting prism used to deviate a beam of light by 45° to 60°, depending on its construction, while neither flipping nor rotating the image. It is named for its

title: What Kate Does

text: What Kate Does "What Kate Does" is the 106th television episode of the American Broadcasting Company's "Lost" and third episode of the sixth season. It was written by executive producers Edward Kitsis and Adam Horowitz and directed in September 2009 by Paul Edwards. "What Kate Does" was first aired February 9, 2010, on ABC in the United States and on CTV in Canada. Kate Austen is the character on whom the episode is centered. In December 2007, Kate Austen chases after James "Sawyer" Ford (Josh Holloway), who escapes from the Others' captivity in the island's temple and is grieving over

title: Delta prism

text: the odd parity of three reflections involved. If the base surface is roofed, the number of reflections increases to an even four. The roofed prism thus acts as an image erector, rotating the image without the mirroring effect of the unroofed form. The delta prism is named for its shape being similar to the uppercase Greek letter Δ (delta). Delta prism A delta prism is an optical element providing a compact folded form of the Dove prism. When used in the normal orientation, the prism inverts the image (that is, rotates it 180 degrees); rotating the orientation results in image

title: Nomarski prism

text: is oriented obliquely with respect to the flat surface of the prism. The Nomarski modification causes the light rays to come to a focal point outside the body of the prism, and allows greater flexibility so that when setting up the microscope the prism can be actively focused. Nomarski prism A Nomarski prism is a modification of the Wollaston prism that is used in differential interference contrast microscopy. It is named after its inventor, Polish physicist Georges Nomarski. Like the Wollaston prism, the Nomarski prism consists of two birefringent crystal wedges (e.g. quartz or calcite) cemented together at the hypotenuse

title: Amici roof prism

text: Amici roof prism An Amici roof prism, named for its inventor, the Italian astronomer Giovanni Amici, is a type of reflecting prism used to deviate a beam of light by 90° while simultaneously inverting the image. It is commonly used in the eyepieces of telescopes as an image erecting system. It is sometimes called an Amici prism or right angle roof prism. The non-dispersive Amici roof prism should not be confused with the dispersive Amici prism. The device is shaped like a standard right-angled prism with an additional "roof" section (consisting of two faces meeting at a 90° angle) on

title: Nicol prism

text: Nicols" (abbreviated as XN) is still used to refer to the observing of a sample placed between orthogonally oriented polarizers. In most instruments, however, Nicol prisms have been replaced by other types of polarizers such as Polaroid sheets and Glan–Thompson prisms. Nicol prism A Nicol prism is a type of polarizer, an optical device made from calcite crystal used to produce and analyse plane polarized light. It is made in such a way that it eliminates one of the rays by total internal reflection, i.e. the ordinary ray is eliminated and only the extraordinary ray is transmitted through the prism.

title: Dove prism

text: Dove prism A Dove prism is a type of reflective prism which is used to invert an image. Dove prisms are shaped from a truncated right-angle prism. The Dove prism is named for its inventor, Heinrich Wilhelm Dove. A beam of light travelling parallel to the longitudinal axis, entering one of the sloped faces of the prism undergoes total internal reflection from the inside of the longest (bottom) face and emerges from the opposite sloped face. Images passing through the prism are flipped (mirrored), and because only one reflection takes place, the image is also inverted but not laterally transposed.

title: Schmidt–Pechan prism

text: or revert (flip) the image, depending on the orientation of the prism, but not both at the same time. For the Schmidt-Pechan design, the upper prism from the Pechan design is replaced with a Schmidt roof prism, so the Schmidt–Pechan prism can both invert and revert the image and so act as an image rotator. The lower prism is known as a half-penta prism or Bauernfeind prism. The image's handedness is not changed by the Schmidt-Pechan. The design of the two prisms is such that the entrance beam and exit beam are coaxial, i.e. the Schmidt–Pechan prism does not deviate

title: Prism

text: output of a laser diode. Rhomboid prisms are used to laterally displace a beam of light without inverting the image. Deck prisms were used on sailing ships to bring daylight below deck, since candles and kerosene lamps are a fire hazard on wooden ships. By shifting corrective lenses off axis, images seen through them can be displaced in the same way that a prism displaces images. Eye care professionals use prisms, as well as lenses off axis, to treat various orthoptics problems: Prism spectacles with a single prism perform a relative displacement of the two eyes, thereby correcting eso-, exo,

title: PRISM (surveillance program)

text: them directly, but said, "We do not know the nature of data or information sought [as part of PRISM]. Even the external ministry does not have any idea." The media felt that Khurshid's defence of PRISM was because the India government was rolling out the Central Monitoring System (CMS), which is similar to the PRISM program. Khurshid's comments were criticized by the Indian media, as well as opposition party CPI(M) who stated, "The UPA government should have strongly protested against such surveillance and bugging. Instead, it is shocking that Khurshid has sought to justify it. This shameful remark has come

title: What She Does Best

text: other singles charted far outside the Top 40. "How Many Hearts" was the last single Anderson released, and it peaked at No. 69 on the country charts in 1989. The album's cover shows Anderson leaning on a fancy sports car, wearing a classic 1980s outfit. What She Does Best What She Does Best is a studio album by country singer Lynn Anderson, released in 1988. It was her only album with Mercury records. Notable due to featuring her last charting single, "What She Does Best" did not chart and was commercially unsuccessful. It would be her last album for four

title: What Kate Does

text: week." VanDerWerff of the "LA Times", Ryan of the "Chicago Tribune", Sepinwall of "The Star-Ledger", Jensen of "Entertainment Weekly" and Mark Medley of the "National Post" also found the episode to contain humorous lines. This episode was watched by 11 million American viewers and 1.57 million Canadian viewers. What Kate Does "What Kate Does" is the 106th television episode of the American Broadcasting Company's "Lost" and third episode of the sixth season. It was written by executive producers Edward Kitsis and Adam Horowitz and directed in September 2009 by Paul Edwards. "What Kate Does" was first aired February 9, 2010,

title: Roof prism

text: the two 90° faces usually don't meet in a Porro prism and therefore don't form a roof edge. The multiple internal reflections cause a polarization-dependent phase-lag of the transmitted light, in a manner similar to a Fresnel rhomb. This must be suppressed by multilayer "phase-correction coatings" applied to one of the roof surfaces to avoid unwanted interference effects and a loss of contrast in the image. In a roof prism without a phase-correcting coating, s-polarized and p-polarized light each acquire a different geometric phase as they pass through the upper prism. When the two polarized components are recombined, interference between

title: What She Does Best

text: What She Does Best What She Does Best is a studio album by country singer Lynn Anderson, released in 1988. It was her only album with Mercury records. Notable due to featuring her last charting single, "What She Does Best" did not chart and was commercially unsuccessful. It would be her last album for four years, as Anderson went into a brief retirement and officially retired from releasing singles. The singles from this disc were "Under the Boardwalk" (a cover version of The Drifters' hit), "What He Does Best", and "How Many Hearts". "Under the Boardwalk" reached No. 24; the

title: Does exactly what it says on the tin

text: Does exactly what it says on the tin "It does exactly what it says on the tin" was originally an advertising slogan in the United Kingdom, which then became a common idiomatic phrase. It colloquially means that the name of something is an accurate description of its qualities. It is akin to the previously existing phrases "by name and by nature" and "it lives up to its name". It originated in a series of television advertisements by the woodstain and wood-dye manufacturer Ronseal, initiated in 1994 and still being broadcast . The slogan was created by Liz Whiston and Dave

title: What Kate Does

text: reviews"; however, this was down significantly from the previous episode's 89 and Bonnie Covel of About.com noted that " 'What Kate Does' brought us a bit of negativity. In general, fans just didn't like the episode". "What Kate Does" was largely considered to be a step down from the season premiere in pacing, revelations and writing; Mike Hale of "The New York Times" described the episode as "contemplative", "anticlimactic" and "subdued" and the flash sideways as "kind of boring and seemingly pointless." Chris Carabott of IGN, who gave the episode a score of 7.3 summed up that " 'What Kate

title: Apollo PRISM

text: Apollo PRISM PRISM (Parallel Reduced Instruction Set Multiprocessor) was Apollo Computer's high-performance CPU used in their DN10000 series workstations. It was for some time the fastest microprocessor available, a high fraction of a Cray-1 in a workstation. Hewlett Packard purchased Apollo in 1989, ending development of PRISM, although some of PRISM's ideas were later used in HP's own HP-PA Reduced instruction set computer (RISC) and Itanium processors. PRISM was based on what would be known today as a VLIW-design, while most efforts of the era, 1988, were based on a more "pure" RISC approach. In early RISC designs, the core

title: Porro–Abbe prism

text: Porro–Abbe prism A Porro–Abbe prism (sometimes called a Abbe–Porro prism), named for Ignazio Porro and Ernst Abbe, is a type of reflection prism used in some optical instruments to alter the orientation of an image. It is a variant of the more common double Porro prism configuration. It is made from a piece of glass shaped like four right-angled reflecting prisms joined face-to-face in a twisted fashion. Light enters one flat face, is internally reflected four times from the sloping faces of the prism, and exits the second flat face offset from, but in the same direction as the entrance

title: Schmidt–Pechan prism

text: prism can be further improved by using a dielectric coating rather than a metallic mirror coating. This causes the prism surfaces to act as a dielectric mirror. A well-designed dielectric coating can provide a reflectivity of more than 99% across the visible light spectrum. This reflectivity is much improved compared to either an aluminum or silver mirror coating and the performance of the Schmidt–Pechan prism is similar to the Porro prism or the Abbe–Koenig prism. The necessary mirror coating not only adds an additional manufacturing step, but it makes the Schmidt–Pechan roof prism more lossy than the other image erectors

title: Nicol prism

text: Nicol prism A Nicol prism is a type of polarizer, an optical device made from calcite crystal used to produce and analyse plane polarized light. It is made in such a way that it eliminates one of the rays by total internal reflection, i.e. the ordinary ray is eliminated and only the extraordinary ray is transmitted through the prism. It was the first type of polarizing prism, invented in 1828 by William Nicol (1770–1851) of Edinburgh. It consists of a rhombohedral crystal of Iceland spar (a variety of calcite) that has been cut at an angle of 68° with respect

title: Photoelectric effect

text: with an induction coil between zinc or cadmium terminals, the light from which is very rich in ultra-violet rays. Sunlight is not rich in ultra-violet rays, as these have been absorbed by the atmosphere, and it does not produce nearly so large an effect as the arc-light. Many substances besides metals discharge negative electricity under the action of ultraviolet light: lists of these substances will be found in papers by G. C. Schmidt and O. Knoblauch. In 1839, Alexandre Edmond Becquerel discovered the photovoltaic effect while studying the effect of light on electrolytic cells. Though not equivalent to the photoelectric

title: Dispersive prism

text: angle of the prism (the angle of the edge between the input and output faces) can be widened to increase the spectral dispersion. However it is often chosen so that both the incoming and outgoing light rays hit the surface at around the Brewster angle; beyond the Brewster angle reflection losses increase greatly. Most frequently, dispersive prisms are equilateral (apex angle of 60 degrees) where this is approximately the case. Types of dispersive prism include: There are six grating/prism configurations which are considered to be "classics": A diffraction grating may be ruled onto one face of a prism to form

title: PRISM (surveillance program)

text: disclosures were published by "The Guardian" and "The Washington Post" on June 6, 2013. Subsequent documents have demonstrated a financial arrangement between the NSA's Special Source Operations division (SSO) and PRISM partners in the millions of dollars. Documents indicate that PRISM is "the number one source of raw intelligence used for NSA analytic reports", and it accounts for 91% of the NSA's internet traffic acquired under FISA section 702 authority." The leaked information came to light one day after the revelation that the FISA Court had been ordering a subsidiary of telecommunications company Verizon Communications to turn over to the

title: What Kate Does

text: doesn't quite know how to write a woman of action who's also in love … many of the show's Kate flashbacks are just plain silly … there have been a lot of pretty dire Kate episodes." Whitney Matheson of "USA Today" said that she "wanted to stab Kate with a hot poker" after watching "What Kate Does". Josh Holloway's supporting performance as a grieving Sawyer was commended by Carabott of IGN, who said that his acting on the dock as he cried and revealed to Kate that he was going to ask Juliet to marry him was "one of Josh

title: Wedge prism

text: tree (Figure 2) and DBH must be measured to determine if it should be counted (or, more commonly in practice, every other borderline tree is counted). A tree where the offset section of the tree does not overlap or touch the original bole is an "out" tree (Figure 3) and is not counted. Basal area is estimated by multiplying the count of "in" trees at a given point by the 'factor' of the prism. Prism factor is based on the angle of the prism, and prisms are available in different factors, expressed in both square feet/acre (5, 10, 20 BAF

title: Abbe–Koenig prism

text: Abbe–Koenig prism An Abbe–Koenig prism is a type of reflecting prism, used to invert an image (rotate it by 180°). They are commonly used in binoculars and some telescopes for this purpose. The prism is named after Ernst Abbe and Albert Koenig. The prism is made from two glass prisms, which are optically cemented together to form a symmetric, shallow Vee-shaped assembly. Light enters one face at normal incidence, is internally reflected from a 30° sloped face, and then is reflected from a "roof" (German "Dach") section (consisting of two faces meeting at a 90° angle) at the bottom of

title: Littrow prism

text: Littrow prism In optics, a Littrow prism or Littrow spectrograph or Littrow mirror is a retro-reflecting dispersing prism arranged in such a way that an incident light beam which enters at the Brewster angle undergoes minimal deviation and hence maximum dispersion. Littrow prisms are typically 30°/60°/90° prisms, with a reflective film coating on the surface opposite the 60° angle. It was devised by J. J. von Littrow (1781–1840) of the University of Vienna who made a careful enumeration of stars for each magnitude. Typically Littrow prisms are used in lasers at the end of an optical cavity to offer fine