id stringlengths 14 14 | text stringlengths 9 3.55k | source stringlengths 1 250 |
|---|---|---|
c_2t0fg48o8wp2 | The pre-defined orientation of the sensor is, moreover, restricting the working space of the robot. For untroubled operation of the optical components also stronger soiling/impurification (dust and deposition of weld fume particles) should be avoided, if possible. Exchangeable protective glasses and safety screens in t... | Sensors for arc welding |
c_4j18m7xx3jub | The quality of the surface which is to be measured has substantial influence on the measuring result. If the surface is strongly reflecting, unwanted reflection and faulty measurements may occur, lustreless surfaces are less difficult. Ever-changing surface qualities also lead to problems. | Sensors for arc welding |
c_4m30u33qe9wj | Since optical systems are equipped with semiconductor detectors and comprehensive electronics, it is most important to pay attention to safe electro-magnetic screening. This applies to the sensor, the image processing unit and the connecting cables thereof. Sensor systems with active laser illumination are reacting par... | Sensors for arc welding |
c_c49yu5xdhfrm | If the ambient temperature and thus the wavelength of the active illumination are changing, the light is no longer capable to penetrate through the narrow-band optical filter to the photodetector. Therefore, appropriate screening against the welding process or the cooling of the sensor head is required. Depending on th... | Sensors for arc welding |
c_yyzvlzp7ux83 | The wavelength of the applied systems are often in the field of vision, which means the classification into the hazard classes 3A and 3B. The respective accident prevention regulations must be strictly adhered to. The application of optical sensors demands the consideration of following points: consideration of the res... | Sensors for arc welding |
c_y0xvsopyri6n | In optical spectroscopy, the detectors typically measure the intensity of the light field rather than the electric field because there are no detectors that can directly measure electromagnetic fields in the optical range. However, there are multiple techniques, such as antennas and electro-optical sampling, that can b... | Terahertz spectroscopy and technology |
c_3mi3sazih2um | Therefore, one collects information of semiconductor excitation dynamics completely in time domain, which is the general principle of the terahertz time-domain spectroscopy. By using short THz pulses, a great variety of physical phenomena have already been studied. For unexcited, intrinsic semiconductors one can determ... | Terahertz spectroscopy and technology |
c_w24qcv7uzjhr | The frequency of transversal-optical phonons, to which THz photons can couple, lies for most semiconductors at several THz. Free carriers in doped semiconductors or optically excited semiconductors lead to a considerable absorption of THz photons. Since THz pulses passes through non-metallic materials, they can be used... | Terahertz spectroscopy and technology |
c_30iv7vdf9db8 | In optical storage, constant angular velocity (CAV) is a qualifier for the rated speed of any disc containing information, and may also be applied to the writing speed of recordable discs. A drive or disc operating in CAV mode maintains a constant angular velocity, contrasted with a constant linear velocity (CLV). A ty... | Partial constant angular velocity |
c_e0vr6qs5z5gg | In contrast, in CLV mode, the spindle motor speed varies so that the medium passes by the head at the same speed regardless of where on the disk the head is positioned. If the disk is recorded at the same areal density throughout, then when read or written in CAV mode, the data rate is higher for the outer tracks than ... | Partial constant angular velocity |
c_lg8mw7c5w67y | In optical storage, constant linear velocity (CLV) is a qualifier for the rated speed of an optical disc drive, and may also be applied to the writing speed of recordable discs. CLV implies that the angular velocity (i.e. rpm) varies during an operation, as contrasted with CAV modes. The concept of constant linear velo... | Zoned constant linear velocity |
c_x7lyxgdhyupk | In optical storage, three types of storage are usually recognized, and given customary abbreviations: read-only ("ROM"), Write once ("R") and read/writable ("RW", or for Blu-ray, "E" for "erasable"). Examples: CD-ROM represents the CD format, in its pre-recorded "read only" use DVD+R represents a DVD "+" disc which can... | Comparison of popular optical data-storage systems |
c_9bkxbyw9hajk | In optical systems composed of lenses, the position, magnitude and errors of the image depend upon the refractive indices of the glass employed (see Lens (optics) and Monochromatic aberration, above). Since the index of refraction varies with the color or wavelength of the light (see dispersion), it follows that a syst... | Optical aberration |
c_ceqoesrwq28s | A system is said to be chromatically under-corrected when it shows the same kind of chromatic error as a thin positive lens, otherwise it is said to be overcorrected.If, in the first place, monochromatic aberrations be neglected — in other words, the Gaussian theory be accepted — then every reproduction is determined b... | Optical aberration |
c_e1kyi4flyi6f | In this manner the conditions are maintained that any one constant of reproduction is equal for two different colors, i.e. this constant is achromatized. For example, it is possible, with one thick lens in air, to achromatize the position of a focal plane of the magnitude of the focal length. If all three constants of ... | Optical aberration |
c_blrmhwy578tz | In a plane containing the image point of one color, another colour produces a disk of confusion; this is similar to the confusion caused by two zones in spherical aberration. For infinitely distant objects the radius Of the chromatic disk of confusion is proportional to the linear aperture, and independent of the focal... | Optical aberration |
c_b7y23j8p69jw | )Examples: Newton failed to perceive the existence of media of different dispersive powers required by achromatism; consequently he constructed large reflectors instead of refractors. James Gregory and Leonhard Euler arrived at the correct view from a false conception of the achromatism of the eye; this was determined ... | Optical aberration |
c_450jsn7aaavk | )Glass with weaker dispersive power (greater v {\displaystyle v} ) is named crown glass; that with greater dispersive power, flint glass. For the construction of an achromatic collective lens ( f {\displaystyle f} positive) it follows, by means of equation (4), that a collective lens I. of crown glass and a dispersive ... | Optical aberration |
c_1br8o32un34c | For an achromatic dispersive lens the converse must be adopted. This is, at the present day, the ordinary type, e.g., of telescope objective; the values of the four radii must satisfy the equations (2) and (4). Two other conditions may also be postulated: one is always the elimination of the aberration on the axis; the... | Optical aberration |
c_y7ztii1skva1 | In practice, however, it is often more useful to avoid the second condition by making the lenses have contact, i.e. equal radii. According to P. Rudolph (Eder's Jahrb. | Optical aberration |
c_mrrzn7ju3aa3 | f. Photog., 1891, 5, p. | Optical aberration |
c_xyynb5csxe99 | 225; 1893, 7, p. 221), cemented objectives of thin lenses permit the elimination of spherical aberration on the axis, if, as above, the collective lens has a smaller refractive index; on the other hand, they permit the elimination of astigmatism and curvature of the field, if the collective lens has a greater refractiv... | Optical aberration |
c_kjiegenod05w | 289). Should the cemented system be positive, then the more powerful lens must be positive; and, according to (4), to the greater power belongs the weaker dispersive power (greater v {\displaystyle v} ), that is to say, crown glass; consequently the crown glass must have the greater refractive index for astigmatic and ... | Optical aberration |
c_edaz9i0ek2lt | If the lenses I. and II. be cemented and have the same refractive index for one color, then its effect for that one color is that of a lens of one piece; by such decomposition of a lens it can be made chromatic or achromatic at will, without altering its spherical effect. If its chromatic effect ( d f / f {\displaystyl... | Optical aberration |
c_ou0j1u7eb3b5 | For example, the condition for achromatism (4) for two thin lenses in contact is fulfilled in only one part of the spectrum, since d n 2 / d n 1 {\displaystyle dn_{2}/dn_{1}} varies within the spectrum. This fact was first ascertained by J. Fraunhofer, who defined the colors by means of the dark lines in the solar spec... | Optical aberration |
c_2015i5yt7mhz | In optical systems such as lighting and lasers, the energy conversion efficiency is often referred to as wall-plug efficiency. The wall-plug efficiency is the measure of output radiative-energy, in watts (joules per second), per total input electrical energy in watts. The output energy is usually measured in terms of a... | Conversion efficiency |
c_69q6gbo7dhf4 | Instead of using watts, the power of a light source to produce wavelengths proportional to human perception is measured in lumens. The human eye is most sensitive to wavelengths of 555 nanometers (greenish-yellow) but the sensitivity decreases dramatically to either side of this wavelength, following a Gaussian power-c... | Conversion efficiency |
c_yahs04917eon | Yellow and green, for example, make up more than 50% of what the eye perceives as being white, even though in terms of radiant energy white-light is made from equal portions of all colors (i.e.: a 5 mW green laser appears brighter than a 5 mW red laser, yet the red laser stands-out better against a white background). T... | Conversion efficiency |
c_wh16s1xu1wn1 | The effectiveness of a light source to convert electrical energy into wavelengths of visible light, in proportion to the sensitivity of the human eye, is referred to as luminous efficacy, which is measured in units of lumens per watt (lm/w) of electrical input-energy. Unlike efficacy (effectiveness), which is a unit of... | Conversion efficiency |
c_p2dsa8jqqdce | The amount of energy carried by a photon of light is determined by its wavelength. In lumens, this energy is offset by the eye's sensitivity to the selected wavelengths. For example, a green laser pointer can have greater than 30 times the apparent brightness of a red pointer of the same power output. | Conversion efficiency |
c_emel972mb1e7 | At 555 nm in wavelength, 1 watt of radiant energy is equivalent to 685 lumens, thus a monochromatic light source at this wavelength, with a luminous efficacy of 685 lm/w, would have a luminous efficiency of 100%. The theoretical-maximum efficacy lowers for wavelengths at either side of 555 nm. For example, low-pressure... | Conversion efficiency |
c_b9v1jel1fwfr | The theoretical-maximum efficacy at that wavelength is 525 lm/w, so the lamp has a luminous efficiency of 38.1%. Because the lamp is monochromatic, the luminous efficiency nearly matches the wall-plug efficiency of < 40%.Calculations for luminous efficiency become more complex for lamps that produce white light or a mi... | Conversion efficiency |
c_ir0ngs0em39p | A xenon flashtube has a typical wall-plug efficiency of 50–70%, exceeding that of most other forms of lighting. Because the flashtube emits large amounts of infrared and ultraviolet radiation, only a portion of the output energy is used by the eye. | Conversion efficiency |
c_ex3p712or564 | The luminous efficacy is therefore typically around 50 lm/w. However, not all applications for lighting involve the human eye nor are restricted to visible wavelengths. For laser pumping, the efficacy is not related to the human eye so it is not called "luminous" efficacy, but rather simply "efficacy" as it relates to ... | Conversion efficiency |
c_c5z1dgdlc3u6 | Krypton flashtubes are often chosen for pumping Nd:YAG lasers, even though their wall-plug efficiency is typically only ~ 40%. Krypton's spectral lines better match the absorption lines of the neodymium-doped crystal, thus the efficacy of krypton for this purpose is much higher than xenon; able to produce up to twice t... | Conversion efficiency |
c_h46z08xe4yje | All of these terms refer to the amount of energy and lumens as they exit the light source, disregarding any losses that might occur within the lighting fixture or subsequent output optics. Luminaire efficiency refers to the total lumen-output from the fixture per the lamp output.With the exception of a few light source... | Conversion efficiency |
c_dykestebujcf | Similarly, fluorescent lamps also convert the electricity using a ballast (electronic efficiency). The electricity is then converted into light energy by the electrical arc (electrode efficiency and discharge efficiency). The light is then transferred to a fluorescent coating that only absorbs suitable wavelengths, wit... | Conversion efficiency |
c_6gzxkbazcub6 | The number of photons absorbed by the coating will not match the number then reemitted as fluorescence (quantum efficiency). Finally, due to the phenomenon of the Stokes shift, the re-emitted photons will have a longer wavelength (thus lower energy) than the absorbed photons (fluorescence efficiency). In very similar f... | Conversion efficiency |
c_pqa1ech1rcxc | In optical systems, especially those involving interferometry, the alignment of each component must be extremely accurate—precise down to a fraction of a wavelength—usually a few hundred nanometers. Even small vibrations or strain in the table on which the elements are set up might lead to complete failure of an experi... | Air table |
c_dndgwo578ezx | In optical testing a Ronchi test is a method of determining the surface shape (figure) of a mirror used in telescopes and other optical devices. | Ronchi test |
c_z24jt5x4fspo | In optical triangulation, the satellite can be used as a very high target for triangulation and can be used to ascertain the geometric relationship between multiple observing stations. Optical triangulation with the BC-4, PC-1000, MOTS, or Baker Nunn cameras consisted of photographic observations of a satellite, or fla... | Satellite geodesy |
c_flli4hg7l083 | Geodetic positioning work with cameras was usually performed with one camera observing simultaneously with one or more other cameras. Camera systems are weather dependent and that is one major reason why they fell out of use by the 1980s. : 51 Examples: PAGEOS, Project Echo, ANNA 1B | Satellite geodesy |
c_atu5fow8xalf | In optics (especially telescopes), the coma (), or comatic aberration, in an optical system refers to aberration inherent to certain optical designs or due to imperfection in the lens or other components that results in off-axis point sources such as stars appearing distorted, appearing to have a tail (coma) like a com... | Coma aberration |
c_0bg2nba59gfq | In optics (particularly in fiber optics) a loss that takes place at discontinuities of refractive index, especially at an air-glass interface such as a fiber endface. At those interfaces, a fraction of the optical signal is reflected back toward the source. This reflection phenomenon is also called "Fresnel reflection ... | Return loss |
c_xu3wd7pdkkr3 | The measurement of ORL is becoming more important in the characterization of optical networks as the use of wavelength-division multiplexing increases. These systems use lasers that have a lower tolerance for ORL, and introduce elements into the network that are located in close proximity to the laser. ORL ( d B ) = 10... | Return loss |
c_h1om4sdc3o1a | In optics and acoustics, evanescent waves are formed when waves traveling in a medium undergo total internal reflection at its boundary because they strike it at an angle greater than the so-called critical angle. The physical explanation for the existence of the evanescent wave is that the electric and magnetic fields... | Evanescent wave |
c_487b02gtt773 | The evanescent wave from an optical fiber can be used in a gas sensor, and evanescent waves figure in the infrared spectroscopy technique known as attenuated total reflectance. In electrical engineering, evanescent waves are found in the near-field region within one third of a wavelength of any radio antenna. During no... | Evanescent wave |
c_tu9isn1tyqjo | Recently, a graphene-based Bragg grating (one-dimensional photonic crystal) has been fabricated and demonstrated its competence for excitation of surface electromagnetic waves in the periodic structure using a prism coupling technique.In quantum mechanics, the evanescent-wave solutions of the Schrödinger equation give ... | Evanescent wave |
c_eqjcuekwa4xx | Conventional optical systems capture only the information in the propagating waves and hence are subject to the diffraction limit. Systems that capture the information contained in evanescent waves, such as the superlens and near field scanning optical microscopy, can overcome the diffraction limit; however these syste... | Evanescent wave |
c_erxbq08mqa4v | In optics and electromagnetics in general, "reflection coefficient" can refer to either the amplitude reflection coefficient described here, or the reflectance, depending on context. Typically, the reflectance is represented by a capital R, while the amplitude reflection coefficient is represented by a lower-case r. Th... | Reflection loss |
c_mfb0x5l6mivf | In optics and especially laser science, the Rayleigh length or Rayleigh range, z R {\displaystyle z_{\mathrm {R} }} , is the distance along the propagation direction of a beam from the waist to the place where the area of the cross section is doubled. A related parameter is the confocal parameter, b, which is twice the... | Rayleigh length |
c_yxr1p9nzix10 | In optics and especially telescope making, sagitta or sag is a measure of the glass removed to yield an optical curve. It is approximated by the formula S ( r ) ≈ r 2 2 × R {\displaystyle S(r)\approx {\frac {r^{2}}{2\times R}}} ,where R is the radius of curvature of the optical surface. The sag S(r) is the displacement... | Sagitta (optics) |
c_mpdm8a5jb6n5 | In optics and imaging, the term "deconvolution" is specifically used to refer to the process of reversing the optical distortion that takes place in an optical microscope, electron microscope, telescope, or other imaging instrument, thus creating clearer images. It is usually done in the digital domain by a software al... | Deconvolution |
c_flsu5e8sx4kn | The usual method is to assume that the optical path through the instrument is optically perfect, convolved with a point spread function (PSF), that is, a mathematical function that describes the distortion in terms of the pathway a theoretical point source of light (or other waves) takes through the instrument. Usually... | Deconvolution |
c_dbkj5az1g0et | The result is the original, undistorted image. In practice, finding the true PSF is impossible, and usually an approximation of it is used, theoretically calculated or based on some experimental estimation by using known probes. Real optics may also have different PSFs at different focal and spatial locations, and the ... | Deconvolution |
c_39ir27dzlzu2 | The accuracy of the approximation of the PSF will dictate the final result. Different algorithms can be employed to give better results, at the price of being more computationally intensive. Since the original convolution discards data, some algorithms use additional data acquired at nearby focal points to make up some... | Deconvolution |
c_giynsj64gzag | Regularization in iterative algorithms (as in expectation-maximization algorithms) can be applied to avoid unrealistic solutions. When the PSF is unknown, it may be possible to deduce it by systematically trying different possible PSFs and assessing whether the image has improved. This procedure is called blind deconvo... | Deconvolution |
c_v96qjunzdyib | Blind deconvolution is a well-established image restoration technique in astronomy, where the point nature of the objects photographed exposes the PSF thus making it more feasible. It is also used in fluorescence microscopy for image restoration, and in fluorescence spectral imaging for spectral separation of multiple ... | Deconvolution |
c_e3qd7id9o2v1 | In optics and in wave propagation in general, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency; sometimes the term chromatic dispersion is used for specificity to optics in particular. A medium having this common property may be termed a dispersive medium (plural dispersive me... | Dispersion measure |
c_17lc33jvyrp3 | Within optics, dispersion is a property of telecommunication signals along transmission lines (such as microwaves in coaxial cable) or the pulses of light in optical fiber. In optics, one important and familiar consequence of dispersion is the change in the angle of refraction of different colors of light, as seen in t... | Dispersion measure |
c_7nmp6wuh2ns1 | In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German ... | Abbe number |
c_wlqzjp7l8800 | The Abbe number, Vd, of a material is defined as V D = n d − 1 n F − n C , {\displaystyle V_{D}={\frac {n_{d}-1}{n_{F}-n_{C}}},} where nC, nd and nF are the refractive indices of the material at the wavelengths of the Fraunhofer C, d, and F spectral lines (656.3 nm, 587.56 nm, and 486.1 nm respectively). This formulati... | Abbe number |
c_vz7n5prpv5du | For non-visible spectral lines the term V-number is more commonly used. The more general formulation defined as, V = n center − 1 n short − n long , {\displaystyle V={\frac {n_{\text{center}}-1}{n_{\text{short}}-n_{\text{long}}}},} where nshort, ncenter and nlong are the refractive indices of the material at three diff... | Abbe number |
c_8oaxs87b6i5c | Abbe numbers are used to classify glass and other optical materials in terms of their chromaticity. For example, the higher dispersion flint glasses have V < 55 whereas the lower dispersion crown glasses have larger Abbe numbers. Values of V range from below 25 for very dense flint glasses, around 34 for polycarbonate ... | Abbe number |
c_m1eq13rtj2v1 | In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an "acceptable" focus. As the hyperfocal distance is the focus distance giving the maximum depth of field, it is the most desirable distance to set the focus of a fixed-focus camera. The hyperfocal distance is enti... | Hyperfocal distance |
c_vpjw2rqoz7l2 | Louis Derr in 1906 may have been the first to derive a formula for hyperfocal distance. Rudolf Kingslake wrote in 1951 about the two methods of measuring hyperfocal distance. Some cameras have their hyperfocal distance marked on the focus dial. For example, on the Minox LX focusing dial there is a red dot between 2 m a... | Hyperfocal distance |
c_ie72dnnfnybn | In optics and photography, infinity focus is the state where a lens or other optical system forms an image of an object an infinite distance away. This corresponds to the point of focus for parallel rays. The image is formed at the focal point of the lens. In simple two lens systems such as a refractor telescope, the o... | Infinity focus |
c_rur5vv26yp3l | The magnification is equal to the focal length of the objective lens divided by the focal length of the eyepiece.In practice, not all photographic lenses are capable of achieving infinity focus by design. A lens used with an adapter for close-up focusing, for example, may not be able to focus to infinity. Failure of th... | Infinity focus |
c_1p8kuz4yg2dz | All optics are subject to manufacturing tolerances; even with perfect manufacture, optical trains experience thermal expansion. Focus mechanisms must accommodate part variations; even custom-built systems may have some means of adjustment. For example, telescopes such as the Mars Orbiter Camera, which are nominally set... | Infinity focus |
c_8vqfnkbcro1l | In optics and photonics, the concept of local density of states refers to the states that can be occupied by a photon. For light it is usually measured by fluorescence methods, near-field scanning methods or by cathodoluminescence techniques. For different photonic structures, the LDOS have different behaviors and they... | Density of states |
c_lmby91cquis1 | The LDOS are still in photonic crystals but now they are in the cavity. In this case, the LDOS can be much more enhanced and they are proportional with Purcell enhancements of the spontaneous emission. Similar LDOS enhancement is also expected in plasmonic cavity. | Density of states |
c_3spcvb86dmeh | However, in disordered photonic nanostructures, the LDOS behave differently. They fluctuate spatially with their statistics are proportional to the scattering strength of the structures. In addition, the relationship with the mean free path of the scattering is trivial as the LDOS can be still strongly influenced by th... | Density of states |
c_3ph3yd7saxgd | In optics and signal processing, wavefront coding refers to the use of a phase modulating element in conjunction with deconvolution to extend the depth of field of a digital imaging system such as a video camera. Wavefront coding falls under the broad category of computational photography as a technique to enhance the ... | Wavefront coding |
c_fnjbhlmbbbf8 | In optics he analyzed, partially with Vasily Fursov, spectral line broadening in gases at large densities (1936—1938). A new suggestion in these works was to use long range collective interactions between atoms for a correct description of spectra line broadening at large densities. | Anatoly Vlasov |
c_gewyyyh61fhw | In optics phase detectors are also known as interferometers. For pulsed (amplitude modulated) light, it is said to measure the phase between the carriers. It is also possible to measure the delay between the envelopes of two short optical pulses by means of cross correlation in a nonlinear crystal. And it is possible t... | Phase comparator |
c_iy3fcajsys2k | In optics the Lagrange invariant is a measure of the light propagating through an optical system. It is defined by H = n u ¯ y − n u y ¯ {\displaystyle H=n{\overline {u}}y-nu{\overline {y}}} ,where y and u are the marginal ray height and angle respectively, and ȳ and ū are the chief ray height and angle. n is the ambie... | Lagrange invariant |
c_lgb1e86orpdx | For a given optical system, the Lagrange invariant is a constant throughout all space, that is, it is invariant upon refraction and transfer. The optical invariant is a generalization of the Lagrange invariant which is formed using the ray heights and angles of any two rays. For these rays, the optical invariant is a c... | Lagrange invariant |
c_jptou1yon3pd | In optics the Smith–Helmholtz invariant is an invariant quantity for paraxial beams propagating through an optical system. Given an object at height y ¯ {\displaystyle {\bar {y}}} and an axial ray passing through the same axial position as the object with angle u {\displaystyle u} , the invariant is defined by H = n y ... | Smith-Helmholtz invariant |
c_4zcikf36f8pi | Typically the two points of most interest are the object point and the final image point. The Smith–Helmholtz invariant has a close connection with the Abbe sine condition. The paraxial version of the sine condition is satisfied if the ratio n u / n ′ u ′ {\displaystyle nu/n'u'} is constant, where u {\displaystyle u} a... | Smith-Helmholtz invariant |
c_pp2mjdkmc1gp | The Smith–Helmholtz invariant implies that the lateral magnification, y / y ′ {\displaystyle y/y'} is constant if and only if the sine condition is satisfied.The Smith–Helmholtz invariant also relates the lateral and angular magnification of the optical system, which are and u ′ / u {\displaystyle u'/u} respectively. A... | Smith-Helmholtz invariant |
c_ebo4jby71dwo | In optics the noise-equivalent flux density (NEFD) or noise-equivalent irradiance (NEI) of a system is the level of flux density required to be equivalent to the noise present in the system. It is a measure used by astronomers in determining the accuracy of observations.The NEFD can be related to a light detector's noi... | Noise-equivalent flux density |
c_v1w1iqnms9ds | In optics, Cauchy's transmission equation is an empirical relationship between the refractive index and wavelength of light for a particular transparent material. It is named for the mathematician Augustin-Louis Cauchy, who defined it in 1837. | Cauchy's equation |
c_g3tckwi78k7c | In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle θ between the observer's line of sight and the surface normal; I = I0 cos θ. The law is also known as th... | Lambert's cosine law |
c_ftgg77grnghk | This means, for example, that to the human eye it has the same apparent brightness. It has the same radiance because, although the emitted power from a given area element is reduced by the cosine of the emission angle, the solid angle, subtended by surface visible to the viewer, is reduced by the very same amount. Beca... | Lambert's cosine law |
c_oz7i25wd32t5 | In optics, Matthiessen's ratio is the ratio between the distance from the centre of the lens to the retina, versus the lens radius.This is of particular importance in fish, where the value may decrease from as high as 3.6 to 2.3, decreasing the focal ratio of the lens. A higher focal ratio is thought to compensate for ... | Matthiessen's ratio |
c_avs6evnl37vt | In optics, Wadsworth's constant-deviation prism-mirror system (or Wadsworth constant deviation mounting) is a method to arrange a prism or diffraction grating and a mirror on a turntable to ensure that rays of light emerge in a fixed direction. Typically, light entering via a slit is directed into the prism by a lens. ... | Wadsworth constant deviation system |
c_wqspdh0w91vb | Rotating the prism through its entire range of motion enables the entire spectrum to be analyzed.An analytical proof for the arrangement was given by Wadsworth, followed almost three decades later with a geometric proof by Gibbs and Collins. It is considered a "classic" prism configuration being versatile on its own or... | Wadsworth constant deviation system |
c_kxhou1wpshhb | In optics, a Fabry–Pérot interferometer (FPI) or etalon is an optical cavity made from two parallel reflecting surfaces (i.e.: thin mirrors). Optical waves can pass through the optical cavity only when they are in resonance with it. It is named after Charles Fabry and Alfred Perot, who developed the instrument in 1899.... | Fabry-Perot laser |
c_92kf5nsfa676 | In optics, a Gaussian beam is a beam of electromagnetic radiation with high monochromaticity whose amplitude envelope in the transverse plane is given by a Gaussian function; this also implies a Gaussian intensity (irradiance) profile. This fundamental (or TEM00) transverse Gaussian mode describes the intended output o... | Laguerre-Gaussian mode |
c_blb16wqcpqm9 | The electric and magnetic field amplitude profiles along any such circular Gaussian beam (for a given wavelength and polarization) are determined by a single parameter: the so-called waist w0. At any position z relative to the waist (focus) along a beam having a specified w0, the field amplitudes and phases are thereby... | Laguerre-Gaussian mode |
c_hnb1pwb07r41 | Beams with elliptical cross-sections, or with waists at different positions in z for the two transverse dimensions (astigmatic beams) can also be described as Gaussian beams, but with distinct values of w0 and of the z = 0 location for the two transverse dimensions x and y. Arbitrary solutions of the paraxial Helmholtz... | Laguerre-Gaussian mode |
c_88nujsdehber | Although there are other possible modal decompositions, these families of solutions are the most useful for problems involving compact beams, that is, where the optical power is rather closely confined along an axis. Even when a laser is not operating in the fundamental Gaussian mode, its power will generally be found ... | Laguerre-Gaussian mode |
c_7poxndid0z18 | In optics, a Gires–Tournois etalon (also known as Gires–Tournois interferometer) is a transparent plate with two reflecting surfaces, one of which has very high reflectivity, ideally unity. Due to multiple-beam interference, light incident on a Gires–Tournois etalon is (almost) completely reflected, but has an effectiv... | Gires–Tournois etalon |
c_e9eq8wkv3h4f | In optics, a Littrow prism, or Littrow mirror, originally part of a Littrow spectrograph, 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 prism |
c_a4wb4xhm3cs5 | In optics, a Mangin mirror is a negative meniscus lens with the reflective surface on the rear side of the glass forming a curved mirror that reflects light without spherical aberration if certain conditions are met. This reflector was invented in 1874 by a French officer Alphonse Mangin as an improved catadioptric ref... | Mangin mirror |
c_heyxzp392bvi | 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. | Porro prism |
c_cojml9auk2kk | In optics, a Rayleigh interferometer is a type of interferometer which employs two beams of light from a single source. The two beams are recombined after traversing two optical paths, and the interference pattern after recombination allows the determination of the difference in path lengths. | Rayleigh interferometer |
c_ah08gscsxev0 | In optics, a caustic or caustic network is the envelope of light rays which have been reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. The caustic is a curve or surface to which each of the light rays is tangent, defining a boundary of an envelope of r... | Optical caustics |
c_g7poa1grl91y | In optics, a collimator may consist of a curved mirror or lens with some type of light source and/or an image at its focus. This can be used to replicate a target focused at infinity with little or no parallax. In lighting, collimators are typically designed using the principles of nonimaging optics.Optical collimators... | Collimator |
c_8lrcafgrafrd | A surveying camera may be collimated by setting its fiduciary markers so that they define the principal point, as in photogrammetry. Optical collimators are also used as gun sights in the collimator sight, which is a simple optical collimator with a cross hair or some other reticle at its focus. The viewer only sees an... | Collimator |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.