text:
Transparency and translucency
From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
See also: Translucence (disambiguation), Transparency (disambiguation), Transparent (TV series), and Translucent (manga)
Dichroic filters are created using optically transparent materials.
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without being scattered. On a macroscopic scale (one where the dimensions investigated are much, much larger than the wavelength of the photons in question), the photons can be said to follow Snell's Law. Translucency (also called translucence or translucidity) is a superset of transparency: it allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces where there is a change in index of refraction, or internally. In other words, a translucent medium allows the transport of light while a transparent medium not only allows the transport of light but allows for image formation. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposite property of translucency is opacity.
When light encounters a material, it can interact with it in several different ways. These interactions depend on the wavelength of the light and the nature of the material. Photons interact with an object by some combination of reflection, absorption and transmission. Some materials, such as plate glass and clean water, transmit much of the light that falls on them and reflect little of it; such materials are called optically transparent. Many liquids and aqueous solutions are highly transparent. Absence of structural defects (voids, cracks, etc.) and molecular structure of most liquids are mostly responsible for excellent optical transmission.
Materials which do not transmit light are called opaque. Many such substances have a chemical composition which includes what are referred to as absorption centers. Many substances are selective in their absorption of white light frequencies. They absorb certain portions of the visible spectrum while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation. This is what gives rise to color. The attenuation of light of all frequencies and wavelengths is due to the combined mechanisms of absorption and scattering.[1]
Transparency can provide almost perfect camouflage for animals able to achieve it. This is easier in dimly-lit or turbid seawater than in good illumination. Many marine animals such as jellyfish are highly transparent.
Comparisons of 1. opacity, 2. translucency, and 3. transparency; behind each panel is a star
Contents
1 Introduction
2 Light scattering in solids
2.1 Transparent ceramics
3 Absorption of light in solids
3.1 UV-Vis: Electronic transitions
3.2 Infrared: Bond stretching
3.3 Transparency in insulators
4 Optical waveguides
4.1 Mechanisms of attenuation
5 As camouflage
6 See also
7 References
8 Further reading
9 External links
Introduction[edit]
With regard to the absorption of light, primary material considerations include:
At the electronic level, absorption in the ultraviolet and visible (UV-Vis) portions of the spectrum depends on whether the electron orbitals are spaced (or "quantized") such that they can absorb a quantum of light (or photon) of a specific frequency, and does not violate selection rules. For example, in most glasses, electrons have no available energy levels above them in range of that associated with visible light, or if they do, they violate selection rules, meaning there is no appreciable absorption in pure (undoped) glasses, making them ideal transparent materials for windows in buildings.
At the atomic or molecular level, physical absorption in the infrared portion of the spectrum depends on the frequencies of atomic or molecular vibrations or chemical bonds, and on selection rules. Nitrogen and oxygen are not greenhouse gases because there is no absorption because there is no molecular dipole moment.
With regard to the scattering of light, the most critical factor is the length scale of any or all of these structural features relative to the wavelength of the light being scattered. Primary material considerations include:
Crystalline structure: whether or not the atoms or molecules exhibit the 'long-range order' evidenced in crystalline solids.
Glassy structure: scattering centers include fluctuations in density or composition.
Microstructure: scattering centers include internal surfaces such as grain boundaries, crystallographic defects and microscopic pores.
Organic materials: scattering centers include fiber and cell structures and boundaries.
Light scattering in solids[edit]
Main article: Light scattering
General mechanism of diffuse reflection
Diffuse reflection - Generally, when light strikes the surface of a (non-metallic and non-glassy) solid material, it bounces off in all directions due to multiple reflections by the microscopic irregularities inside the material (e.g., the grain boundaries of a polycrystalline material, or the cell or fiber boundaries of an organic material), and by its surface, if it is rough. Diffuse reflection is typically characterized by omni-directional reflection angles. Most of the objects visible to the naked eye are identified via diffuse reflection. Another term commonly used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation.[2][3]
Light scattering in liquids and solids depends on the wavelength of the light being scattered. Limits to spatial scales of visibility (using white light) therefore arise, depending on the frequency of the light wave and the physical dimension (or spatial scale) of the scattering center. Visible light has a wavelength scale on the order of a half a micrometer (one millionth of a meter). Scattering centers (or particles) as small as one micrometer have been observed directly in the light microscope (e.g., Brownian motion).[4][5]
Transparent ceramics[edit]
Optical transparency in polycrystalline materials is limited by the amount of light which is scattered by their microstructural features. Light scattering depends on the wavelength of the light. Limits to spatial scales of visibility (using white light) therefore arise, depending on the frequency of the light wave and the physical dimension of the scattering center. For example, since visible light has a wavelength scale on the order of a micrometer, scattering centers will have dimensions on a similar spatial scale. Primary scattering centers in polycrystalline materials include microstructural defects such as pores and grain boundaries. In addition to pores, most of the interfaces in a typical metal or ceramic object are in the form of grain boundaries which separate tiny regions of crystalline order. When the size of the scattering center (or grain boundary) is reduced below the size of the wavelength of the light being scattered, the scattering no longer occurs to any significant extent.
In the formation of polycrystalline materials (metals and ceramics) the size of the crystalline grains is determined largely by the size of the crystalline particles present in the raw material during formation (or pressing) of the object. Moreover, the size of the grain boundaries scales directly with particle size. Thus a reduction of the original particle size well below the wavelength of visible light (about 1/15 of the light wavelength or roughly 600/15 = 40 nanometers) eliminates much of light scattering, resulting in a translucent or even transparent material.
Computer modeling of light transmission through translucent ceramic alumina has shown that microscopic pores trapped near grain boundaries act as primary scattering centers. The volume fraction of porosity had to be reduced below 1% for high-quality optical transmission (99.99 percent of theoretical density). This goal has been readily accomplished and amply demonstrated in laboratories and research facilities worldwide using the emerging chemical processing methods encompassed by the methods of sol-gel chemistry and nanotechnology.[6]
Translucency of a material being used to highlight the structure of a photographic subject
Transparent ceramics have created interest in their applications for high energy lasers, transparent armor windows, nose cones for heat seeking missiles, radiation detectors for non-destructive testing, high energy physics, space exploration, security and medical imaging applications. Large laser elements made from transparent ceramics can be produced at a relatively low cost. These components are free of internal stress or intrinsic birefringence, and allow relatively large doping levels or optimized custom-designed doping profiles. This makes ceramic laser elements particularly important for high-energy lasers.
The development of transparent panel products will have other potential advanced applications including high strength, impact-resistant materials that can be used for domestic windows and skylights. Perhaps more important is that walls and other applications will have improved overall strength, especially for high-shear conditions found in high seismic and wind exposures. If the expected improvements in mechanical properties bear out, the traditional limits seen on glazing areas in today's building codes could quickly become outdated if the window area actually contributes to the shear resistance of the wall.
Currently available infrared transparent materials typically exhibit a trade-off between optical performance, mechanical strength and price. For example, sapphire (crystalline alumina) is very strong, but it is expensive and lacks full transparency throughout the 3–5 micrometer mid-infrared range. Yttria is fully transparent from 3–5 micrometers, but lacks sufficient strength, hardness, and thermal shock resistance for high-performance aerospace applications. Not surprisingly, a combination of these two materials in the form of the yttrium aluminium garnet (YAG) is one of the top performers in the field.
Absorption of light in solids[edit]
When light strikes an object, it usually has not just a single frequency (or wavelength) but many. Objects have a tendency to selectively absorb, reflect or transmit light of certain frequencies. That is, one object might reflect green light while absorbing all other frequencies of visible light. Another object might selectively transmit blue light while absorbing all other frequencies of visible light. The manner in which visible light interacts with an object is dependent upon the frequency of the light, the nature of the atoms in the object, and often the nature of the electrons in the atoms of the object.
Some materials allow much of the light that falls on them to be transmitted through the material without being reflected. Materials that allow the transmission of light waves through them are called optically transparent. Chemically pure (undoped) window glass and clean river or spring water are prime examples of this.
Materials which do not allow the transmission of any light wave frequencies are called opaque. Such substances may have a chemical composition which includes what are referred to as absorption centers. Most materials are composed of materials which are selective in their absorption of light frequencies. Thus they absorb only certain portions of the visible spectrum. The frequencies of the spectrum which are not absorbed are either reflected back or transmitted for our physical observation. In the visible portion of the spectrum, this is what gives rise to color.[7][8]
Absorption centers are largely responsible for the appearance of specific wavelengths of visible light all around us. Moving from longer (0.7 micrometer) to shorter (0.4 micrometer) wavelengths: red, orange, yellow, green and blue (ROYGB) can all be identified by our senses in the appearance of color by the selective absorption of specific light wave frequencies (or wavelengths). Mechanisms of selective light wave absorption include:
Electronic: Transitions in electron energy levels within the atom (e.g., pigments). These transitions are typically in the ultraviolet (UV) and/or visible portions of the spectrum.
Vibrational: Resonance in atomic/molecular vibrational modes. These transitions are typically in the infrared portion of the spectrum.
UV-Vis: Electronic transitions[edit]
In electronic absorption, the frequency of the incoming light wave is at or near the energy levels of the electrons within the atoms which compose the substance. In this case, the electrons will absorb the energy of the light wave and increase their energy state, often moving outward from the nucleus of the atom into an outer shell or orbital.
The atoms that bind together to make the molecules of any particular substance contain a number of electrons (given by the atomic number Z in the periodic chart). Recall that all light waves are electromagnetic in origin. Thus they are affected strongly when coming into contact with negatively charged electrons in matter. When photons (individual packets of light energy) come in contact with the valence electrons of atom, one of several things can and will occur:
A molecule absorbs the photon, some of the energy may be lost via luminescence, fluorescence and phosphorescence.
A molecule absorbs the photon which results in reflection or scattering.
A molecule cannot absorb the energy of the photon and the photon continues on its path. This results in transmission (provided no other absorption mechanisms are active).
Most of the time, it is a combination of the above that happens to the light that hits an object. The states in different materials vary in the range of energy that they can absorb. Most glasses, for example, block ultraviolet (UV) light. What happens is the electrons in the glass absorb the energy of the photons in the UV range while ignoring the weaker energy of photons in the visible light spectrum. But there are also existing special glass types, like special types of borosilicate glass or quartz that are UV-permeable and thus allow a high transmission of ultra violet light.
Thus, when a material is illuminated, individual photons of light can make the valence electrons of an atom transition to a higher electronic energy level. The photon is destroyed in the process and the absorbed radiant energy is transformed to electric potential energy. Several things can happen then to the absorbed energy: it may be re-emitted by the electron as radiant energy (in this case the overall effect is in fact a scattering of light), dissipated to the rest of the material (i.e. transformed into heat), or the electron can be freed from the atom (as in the photoelectric and Compton effects).
Infrared: Bond stretching[edit]
Normal modes of vibration in a crystalline solid
The primary physical mechanism for storing mechanical energy of motion in condensed matter is through heat, or thermal energy. Thermal energy manifests itself as energy of motion. Thus, heat is motion at the atomic and molecular levels. The primary mode of motion in crystalline substances is vibration. Any given atom will vibrate around some mean or average position within a crystalline structure, surrounded by its nearest neighbors. This vibration in two dimensions is equivalent to the oscillation of a clock’s pendulum. It swings back and forth symmetrically about some mean or average (vertical) position. Atomic and molecular vibrational frequencies may average on the order of 1012 cycles per second (Terahertz radiation).
When a light wave of a given frequency strikes a material with particles having the same or (resonant) vibrational frequencies, then those particles will absorb the energy of the light wave and transform it into thermal energy of vibrational motion. Since different atoms and molecules have different natural frequencies of vibration, they will selectively absorb different frequencies (or portions of the spectrum) of infrared light. Reflection and transmission of light waves occur because the frequencies of the light waves do not match the natural resonant frequencies of vibration of the objects. When infrared light of these frequencies strikes an object, the energy is reflected or transmitted.
If the object is transparent, then the light waves are passed on to neighboring atoms through the bulk of the material and re-emitted on the opposite side of the object. Such frequencies of light waves are said to be transmitted.[9][10]
Transparency in insulators[edit]
An object may be not transparent either because it reflects the incoming light or because it absorbs the incoming light. Almost all solids reflect a part and absorb a part of the incoming light.
When light falls onto a block of metal, it encounters atoms that are tightly packed in a regular lattice and a "sea of electrons" moving randomly between the atoms.[11] In metals, most of these are non-bonding electrons (or free electrons) as opposed to the bonding electrons typically found in covalently bonded or ionically bonded non-metallic (insulating) solids. In a metallic bond, any potential bonding electrons can easily be lost by the atoms in a crystalline structure. The effect of this delocalization is simply to exaggerate the effect of the "sea of electrons". As a result of these electrons, most of the incoming light in metals is reflected back, which is why we see a shiny metal surface.
Most insulators (or dielectric materials) are held together by ionic bonds. Thus, these materials do not have free conduction electrons, and the bonding electrons reflect only a small fraction of the incident wave. The remaining frequencies (or wavelengths) are free to propagate (or be transmitted). This class of materials includes all ceramics and glasses.
If a dielectric material does not include light-absorbent additive molecules (pigments, dyes, colorants), it is usually transparent to the spectrum of visible light. Color centers (or dye molecules, or "dopants") in a dielectric absorb a portion of the incoming light. The remaining frequencies (or wavelengths) are free to be reflected or transmitted. This is how colored glass is produced.
Most liquids and aqueous solutions are highly transparent. For example, water, cooking oil, rubbing alcohol, air, and natural gas are all clear. Absence of structural defects (voids, cracks, etc.) and molecular structure of most liquids are chiefly responsible for their excellent optical transmission. The ability of liquids to "heal" internal defects via viscous flow is one of the reasons why some fibrous materials (e.g., paper or fabric) increase their apparent transparency when wetted. The liquid fills up numerous voids making the material more structurally homogeneous.[citation needed]
Light scattering in an ideal defect-free crystalline (non-metallic) solid which provides no scattering centers for incoming light will be due primarily to any effects of anharmonicity within the ordered lattice. Light transmission will be highly directional due to the typical anisotropy of crystalline substances, which includes their symmetry group and Bravais lattice. For example, the seven different crystalline forms of quartz silica (silicon dioxide, SiO2) are all clear, transparent materials.[12]
Optical waveguides[edit]
Propagation of light through a multi-mode optical fiber
A laser beam bouncing down an acrylic rod, illustrating the total internal reflection of light in a multimode optical fiber
Optically transparent materials focus on the response of a material to incoming light waves of a range of wavelengths. Guided light wave transmission via frequency selective waveguides involves the emerging field of fiber optics and the ability of certain glassy compositions to act as a transmission medium for a range of frequencies simultaneously (multi-mode optical fiber) with little or no interference between competing wavelengths or frequencies. This resonant mode of energy and data transmission via electromagnetic (light) wave propagation is relatively lossless.
An optical fiber is a cylindrical dielectric waveguide that transmits light along its axis by the process of total internal reflection. The fiber consists of a core surrounded by a cladding layer. To confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding. The refractive index is the parameter reflecting the speed of light in a material. (Refractive index is the ratio of the speed of light in vacuum to the speed of light in a given medium. The refractive index of vacuum is therefore 1.) The larger the refractive index, the more slowly light travels in that medium. Typical values for core and cladding of an optical fiber are 1.48 and 1.46, respectively.
When light traveling in a dense medium hits a boundary at a steep angle, the light will be completely reflected. This effect, called total internal reflection, is used in optical fibers to confine light in the core. Light travels along the fiber bouncing back and forth off of the boundary. Because the light must strike the boundary with an angle greater than the critical angle, only light that enters the fiber within a certain range of angles will be propagated. This range of angles is called the acceptance cone of the fiber. The size of this acceptance cone is a function of the refractive index difference between the fiber's core and cladding. Optical waveguides are used as components in integrated optical circuits (e.g. combined with lasers or light-emitting diodes, LEDs) or as the transmission medium in local and long haul optical communication systems.
Mechanisms of attenuation[edit]
See also: Light scattering
Light attenuation by ZBLAN and silica fibers
Attenuation in fiber optics, also known as transmission loss, is the reduction in intensity of the light beam (or signal) with respect to distance traveled through a transmission medium. Attenuation coefficients in fiber optics usually use units of dB/km through the medium due to the very high quality of transparency of modern optical transmission media. The medium is usually a fiber of silica glass that confines the incident light beam to the inside. Attenuation is an important factor limiting the transmission of a signal across large distances. In optical fibers the main attenuation source is scattering from molecular level irregularities (Rayleigh scattering)[13] due to structural disorder and compositional fluctuations of the glass structure. This same phenomenon is seen as one of the limiting factors in the transparency of infrared missile domes[citation needed]. Further attenuation is caused by light absorbed by residual materials, such as metals or water ions, within the fiber core and inner cladding. Light leakage due to bending, splices, connectors, or other outside forces are other factors resulting in attenuation.[14][15]
As camouflage[edit]
Many animals of the open sea, like this Aurelia labiata jellyfish, are largely transparent.
Further information: List of camouflage methods
Many marine animals that float near the surface are highly transparent, giving them almost perfect camouflage.[16] However, transparency is difficult for bodies made of materials that have different refractive indices from seawater. Some marine animals such as jellyfish have gelatinous bodies, composed mainly of water; their thick mesogloea is acellular and highly transparent. This conveniently makes them buoyant, but it also makes them large for their muscle mass, so they cannot swim fast, making this form of camouflage a costly trade-off with mobility.[16] Gelatinous planktonic animals are between 50 and 90 percent transparent. A transparency of 50 percent is enough to make an animal invisible to a predator such as cod at a depth of 650 metres (2,130 ft); better transparency is required for invisibility in shallower water, where the light is brighter and predators can see better. For example, a cod can see prey that are 98 percent transparent in optimal lighting in shallow water. Therefore, sufficient transparency for camouflage is more easily achieved in deeper waters.[16] For the same reason, transparency in air is even harder to achieve, but a partial example is found in the glass frogs of the South American rain forest, which have translucent skin and pale greenish limbs.[17] Several Central American species of clearwing (ithomiine) butterflies and many dragonflies and allied insects also have wings which are mostly transparent, a form of crypsis that provides some protection from predators.
See also[edit]
Brillouin scattering
Clarity meter
Colloidal crystal
Haze (optics)
Light scattering
Pellicle mirror
Photonic crystal
Transparent metals
Turbidity
References[edit]
Jump up ^ Fox, M. (2002). Optical Properties of Solids. Oxford University Press.
Jump up ^ Kerker, M. (1969). The Scattering of Light. Academic, New York.
Jump up ^ Mandelstam, L.I. (1926). "Light Scattering by Inhomogeneous Media". Zh. Russ. Fiz-Khim. Ova. 58: 381.
Jump up ^ van de Hulst, H.C. (1981). Light scattering by small particles. New York: Dover. ISBN 0-486-64228-3.
Jump up ^ Bohren, C.F. & Huffmann, D.R. (1983). Absorption and scattering of light by small particles. New York: Wiley.
Jump up ^ Yamashita, I.; et al. (2008). "Transparent Ceramics". J. Am. Ceram. Soc. 91 (3): 813. doi:10.1111/j.1551-2916.2007.02202.x.
Jump up ^ Simmons, J. & Potter, K.S. (2000). Optical Materials. Academic Press.
Jump up ^ Uhlmann, D.R.; et al. (1991). Optical Properties of Glass. Amer. Ceram. Soc.
Jump up ^ Gunzler, H. & Gremlich, H. (2002). IR Spectroscopy: An Introduction. Wiley.
Jump up ^ Stuart, B. (2004). Infrared Spectroscopy: Fundamentals and Applications. Wiley.
Jump up ^ Mott, N.F. & Jones, H. Theory of the Properties of Metals and Alloys. Clarendon Press, Oxford (1936) Dover Publications (1958).
Jump up ^ Griffin, A. (1968). "Brillouin Light Scattering from Crystals in the Hydrodynamic Region". Rev. Mod. Phys. 40 (1): 167. Bibcode:1968RvMP...40..167G. doi:10.1103/RevModPhys.40.167.
Jump up ^ I. P. Kaminow, T. Li (2002), Optical fiber telecommunications IV, Vol.1, p. 223 Archived 2013-05-27 at the Wayback Machine.
Jump up ^ Smith, R.G. (1972). "Optical power handling capacity of low loss optical fibers as determined by stimulated Raman and Brillouin scattering". Appl. Opt. 11 (11): 2489–94. Bibcode:1972ApOpt..11.2489S. doi:10.1364/AO.11.002489. PMID 20119362.
Jump up ^ Archibald, P.S. & Bennett, H.E. (1978). "Scattering from infrared missile domes". Opt. Eng. 17: 647. Bibcode:1978SPIE..133...71A. doi:10.1117/12.956078.
^ Jump up to: a b c Herring, Peter (2002). The Biology of the Deep Ocean. Oxford University Press. ISBN 978-0-19-854956-7. pp. 190–191.
Jump up ^ Naish, D. "Green-boned glass frogs, monkey frogs, toothless toads". Tetrapod zoology. scienceblogs.com. Archived from the original on 11 November 2012. Retrieved 14 February 2013.
Further reading[edit]
Electrodynamics of continuous media, Landau, L. D., Lifshits. E.M. and Pitaevskii, L.P., (Pergamon Press, Oxford, 1984)
Laser Light Scattering: Basic Principles and Practice Chu, B., 2nd Edn. (Academic Press, New York 1992)
Solid State Laser Engineering, W. Koechner (Springer-Verlag, New York, 1999)
Introduction to Chemical Physics, J.C. Slater (McGraw-Hill, New York, 1939)
Modern Theory of Solids, F. Seitz, (McGraw-Hill, New York, 1940)
Modern Aspects of the Vitreous State, J.D.MacKenzie, Ed. (Butterworths, London, 1960)
External links[edit]
UV stability
Properties of Light
UV-Vis Absorption
Infrared Spectroscopy
Brillouin Scattering
Transparent Ceramics
Bulletproof Glass
Transparent ALON Armor
Properties of Optical Materials
What makes glass transparent ?
Brillouin scattering in optical fiber
Thermal IR Radiation and Missile Guidance
show
v
t
e
Glass science topics
Basics
Glass
Glass transition
Supercooling
Formulation
AgInSbTe
Bioglass
Borophosphosilicate glass
Borosilicate glass
Ceramic glaze
Chalcogenide glass
Cobalt glass
Cranberry glass
Crown glass
Flint glass
Fluorosilicate glass
Fused quartz
GeSbTe
Gold ruby glass
Lead glass
Milk glass
Phosphosilicate glass
Photochromic lens glass
Silicate glass
Soda–lime glass
Sodium hexametaphosphate
Soluble glass
Tellurite glass
Thoriated glass
Ultra low expansion glass
Uranium glass
Vitreous enamel
Wood's glass
ZBLAN
Glass-ceramics
Bioactive glass
CorningWare
Glass-ceramic-to-metal seals
Macor
Zerodur
Preparation
Annealing
Chemical vapor deposition
Glass batch calculation
Glass forming
Glass melting
Glass modeling
Ion implantation
Liquidus temperature
Sol-gel technique
Viscosity
Vitrification
Optics
Achromat
Dispersion
Gradient-index optics
Hydrogen darkening
Optical amplifier
Optical fiber
Optical lens design
Photochromic lens
Photosensitive glass
Refraction
Transparent materials
Surface
modification
Anti-reflective coating
Chemically strengthened glass
Corrosion
Dealkalization
DNA microarray
Hydrogen darkening
Insulated glazing
Porous glass
Self-cleaning glass
Sol-gel technique
Tempered glass
Diverse
topics
Glass-coated wire
Safety glass
Glass databases
Glass electrode
Glass fiber reinforced concrete
Glass ionomer cement
Glass microspheres
Glass-reinforced plastic
Glass-to-metal seal
Porous glass
Prince Rupert's drops
Radioactive waste vitrification
Windshield
Glass fiber
Retrieved from "https://en.wikipedia.org/w/index.php?title=Transparency_and_translucency&oldid=849308064"
Categories:
Glass engineering and science
Transparent materials
Dimensionless numbers
Hidden categories:
Webarchive template wayback links
All articles with unsourced statements
Articles with unsourced statements from July 2013
Articles with unsourced statements from November 2010
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
Afrikaans
العربية
Беларуская
Català
Čeština
Dansk
Deutsch
Eesti
Español
Esperanto
Euskara
Français
Galego
한국어
हिन्दी
IsiXhosa
Italiano
עברית
Latviešu
Lietuvių
Македонски
Bahasa Melayu
Nederlands
日本語
Norsk
Norsk nynorsk
Oʻzbekcha/ўзбекча
Plattdüütsch
Polski
Português
Română
Runa Simi
Русский
Simple English
Slovenščina
Svenska
Türkçe
Українська
اردو
中文
31 more
Edit links
This page was last edited on 8 July 2018, at 02:46 (UTC).
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

values: mw-jump-link #mw-head

values: mw-jump-link #p-search

values:
/wiki/Translucence_(disambiguation)
mw-disambig
Translucence (disambiguation)

values:
/wiki/Transparency_(disambiguation)
mw-redirect mw-disambig
Transparency (disambiguation)

attrs: role class

values:
note
hatnote navigation-not-searchable

attrs: alt src width height class srcset data-file-width data-file-height

value: b

values:
/wiki/Snell%27s_Law
mw-redirect
Snell's Law

values:
/wiki/Solar_Light
mw-redirect
Solar Light

values: checkbox button toctogglecheckbox toctogglecheckbox display:none

values:
/wiki/Selection_rules
mw-redirect
Selection rules

values:
/wiki/Molecular_vibrations
mw-redirect
Molecular vibrations

values:
/wiki/Chemical_bonds
mw-redirect
Chemical bonds

values:
/wiki/Molecular_dipole_moment
mw-redirect
Molecular dipole moment

values: Edit section: Light scattering in solids

values:
/wiki/Light_scattering
mw-redirect
Light scattering

values:
/wiki/Grain_boundaries
mw-redirect
Grain boundaries

values:
/wiki/Transparent_ceramic
mw-redirect
Transparent ceramic

values: Edit section: Absorption of light in solids

values:
/wiki/Energy_levels
mw-redirect
Energy levels

values:
/wiki/Vibrational_modes
mw-redirect
Vibrational modes

values: Edit section: UV-Vis: Electronic transitions

values:
/wiki/Periodic_chart
mw-redirect
Periodic chart

values:
/wiki/Negatively_charged
mw-redirect
Negatively charged

values:
/wiki/Valence_electrons
mw-redirect
Valence electrons

values:
/wiki/Compton_effect
mw-redirect
Compton effect

values:
/wiki/Cycles_per_second
mw-redirect
Cycles per second

values: Edit section: Transparency in insulators

values:
/wiki/Sea_of_electrons
mw-redirect
Sea of electrons

values:
/wiki/Conduction_electrons
mw-redirect
Conduction electrons

values:
/wiki/Ceramic_materials
mw-redirect
Ceramic materials

values:
/wiki/Colour_centre_(disambiguation)
mw-disambig
Colour centre (disambiguation)

values: This claim needs references to reliable sources. (July 2013)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values:
/wiki/Direction_(geometry)
mw-redirect
Direction (geometry)

values:
/wiki/Transparent_materials
mw-redirect
Transparent materials

values:
/wiki/Acrylic_glass
mw-redirect
Acrylic glass

values:
/wiki/Fiber_optics
mw-redirect
Fiber optics

values:
/wiki/Acceptance_cone
mw-redirect
Acceptance cone

values:
/wiki/Light-emitting_diodes
mw-redirect
Light-emitting diodes

values: This claim needs references to reliable sources. (November 2010)

values:
/wiki/Clarity_meter
mw-redirect
Clarity meter

values:
/wiki/Transparent_metals
mw-redirect
Transparent metals

values: -moz-column-width: 22em; -webkit-column-width: 22em; column-width: 22em;

values:
nofollow
external text
//doi.org/10.1103/RevModPhys.40.167

values:
nofollow
external text
//doi.org/10.1364/AO.11.002489

values:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/20119362

values:
nofollow
external text
//doi.org/10.1117/12.956078

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values: nowraplinks collapsible collapsed navbox-inner mw-collapsible mw-collapsed mw-made-collapsible

values: Category:Webarchive template wayback links

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from July 2013

values: Category:Articles with unsourced statements from November 2010

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Transparency_and_translucency
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values:
interlanguage-link interwiki-af
display: none;

values: شفافية (بصريات) – Arabic

values: Празрыстасць – Belarusian

values:
interlanguage-link interwiki-be
display: none;

values:
interlanguage-link interwiki-ca
display: none;

values:
interlanguage-link interwiki-cs
display: none;

values:
interlanguage-link interwiki-da
display: none;

values:
interlanguage-link interwiki-de
display: none;

values:
interlanguage-link interwiki-et
display: none;

values:
interlanguage-link interwiki-eo
display: none;

values:
interlanguage-link interwiki-eu
display: none;

values:
interlanguage-link interwiki-gl
display: none;

values:
interlanguage-link interwiki-ko
display: none;

values: पारदर्शिता और पारभासकता – Hindi

values:
https://xh.wikipedia.org/wiki/Ukucaca
Ukucaca – Xhosa
xh
xh
interlanguage-link-target

values:
interlanguage-link interwiki-xh
display: none;

values:
interlanguage-link interwiki-it
display: none;

values: שקיפות (אופטיקה) – Hebrew

values:
interlanguage-link interwiki-he
display: none;

values:
interlanguage-link interwiki-lv
display: none;

values:
interlanguage-link interwiki-lt
display: none;

values: Проѕирност – Macedonian

values:
interlanguage-link interwiki-mk
display: none;

values:
interlanguage-link interwiki-nl
display: none;

values:
interlanguage-link interwiki-ja
display: none;

values:
interlanguage-link interwiki-no
display: none;

values:
interlanguage-link interwiki-nn
display: none;

values:
interlanguage-link interwiki-uz
display: none;

values:
interlanguage-link interwiki-nds
display: none;

values:
interlanguage-link interwiki-pl
display: none;

values:
interlanguage-link interwiki-ro
display: none;

values:
interlanguage-link interwiki-qu
display: none;

values: Прозрачность среды – Russian

values:
interlanguage-link interwiki-simple
display: none;

values:
interlanguage-link interwiki-sl
display: none;

values:
interlanguage-link interwiki-sv
display: none;

values: Optik saydamlık ve yarı saydamlık – Turkish

values:
interlanguage-link interwiki-tr
display: none;

values: Прозорість середовища – Ukrainian

values:
interlanguage-link interwiki-uk
display: none;

values: شفاف امواد – Urdu

values: All languages (initial selection from common choices by you and others)

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Transparency_and_translucency rootpage-Transparency_and_translucency skin-vector action-view