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Jump to navigationJump to searchNew page: Image:lighterstill.jpgright|frame '''Optics''' is the science that describes the behavior and properties of light and the interaction of light with [[m...
[[Image:lighterstill.jpg]][[Image:Optics2_3.jpg|right|frame]]
'''Optics''' is the [[science]] that describes the behavior and properties of [[light]] and the interaction of light with [[matter]]. Optics explains optical [[phenomena]]. The word ''optics'' comes from ''ὀπτική'', meaning ''appearance'' or ''look'' in ancient Greek).
Optics usually describes the behavior of visible, [[infrared]], and [[ultraviolet]] light; however because light is an [[electromagnetic wave]], similar phenomena occur in [[X-ray]]s, [[microwave]]s, [[radio]] waves, and other forms of [[electromagnetic radiation]] and analogous phenomena occur with [[charged particle]] beams. Optics can largely be regarded as a sub-field of [[electromagnetism]]. Some optical phenomena depend on the [[quantum]] nature of light relating some areas of optics to [[quantum mechanics]]. In practice, the vast majority of optical phenomena can be accounted for using the electromagnetic description of light, as described by [[Maxwell's equations]].
The field of optics has its own [[identity]], societies, and conferences. The pure science aspects of the field are often called optical science or optical [[physics]]. Applied optical sciences are often called optical engineering. Applications of optical engineering related specifically to illumination systems are called illumination engineering. Each of these disciplines tends to be quite different in its applications, technical skills, focus, and professional affiliations. More recent innovations in optical engineering are often categorized as [[photonics]] or [[optoelectronics]]. The boundaries between these fields and "optics" are often unclear, and the terms are used differently in different parts of the world and in different areas of industry.
Because of the wide application of the science of "light" to real-world applications, the areas of optical science and optical engineering tend to be very cross-disciplinary. Optical science is a part of many related disciplines including electrical engineering, physics, psychology, medicine (particularly [[ophthalmology]] and [[optometry]]), and others. Additionally, the most complete description of optical behavior, as known to physics, is unnecessarily complicated for most problems, so particular simplified models are used. These limited models adequately describe subsets of optical phenomena while ignoring behavior irrelevant and/or undetectable to the system of interest.
== Classical optics ==
Before [[quantum optics]] became important, optics consisted mainly of the application of classical electromagnetism and its [[high frequency approximation]]s to light. Classical optics divides into two main branches: geometric optics and [[physical optics]].
''Geometric optics'', or ''ray optics'', describes [[light]] propagation in terms of "rays". Rays are bent at the interface between two dissimilar media, and may be curved in a [[medium]] in which the refractive index is a function of position. The "ray" in geometric optics is an abstract object, or "instrument," which is perpendicular to the wavefronts of the actual optical waves. Geometric optics provides rules for propagating these rays through an optical system, which indicates how the actual wavefront will propagate. This is a significant simplification of optics, and fails to account for many important optical effects such as [[diffraction]] and [[polarization]]. It is a good approximation, however, when the wavelength is very small compared with the size of structures with which the light interacts. Geometric optics can be used to describe the geometrical aspects of imaging, including optical aberrations.
Geometric optics is often simplified even further by making the paraxial approximation, or "small angle approximation." The mathematical behavior then becomes linear, allowing optical components and systems to be described by simple matrices. This leads to the techniques of [[Gaussian optics]] and ''paraxial raytracing'', which are used to find first-order properties of optical systems, such as approximate image and object positions and magnifications.
Gaussian beam propagation is an expansion of paraxial optics that provides a more accurate model of coherent radiation like [[laser]] beams. While still using the paraxial approximation, this technique partially accounts for diffraction, allowing accurate calculations of the rate at which a laser beam expands with distance, and the minimum size to which the beam can be focused. Gaussian beam propagation thus bridges the gap between geometric and physical optics.
''Physical optics'' or [[wave optics]] builds on [[Huygens's principle]] and models the propagation of complex wavefronts through optical systems, including both the amplitude and the phase of the wave. This technique, which is usually applied numerically on a computer, can account for diffraction, interference, and polarization effects, as well as other complex effects. Approximations are still generally used, however, so this is not a full electromagnetic wave theory model of the propagation of light. Such a full model is much more computationally demanding, but can be used to solve small-scale problems that require this more accurate treatment.
== Everyday optics ==
Optics is part of everyday life. [[Rainbow]]s and [[mirage]]s are examples of optical [[phenomena]]. Many people benefit from eyeglasses or contact lenses, and optics are used in many consumer goods including cameras. Superimposition of periodic structures, for example transparent tissues with a grid structure, produces shapes known as [[moiré pattern]]s. Superimposition of periodic transparent patterns comprising parallel opaque lines or curves produces [[line moiré]] patterns.
== References ==
* Optics (4th ed.) Pearson Education, ISBN 0-8053-8566-5}}
* Physics for Scientists and Engineers (6th ed.) ISBN 0-534-40842-7
* Physics for Scientists and Engineers: Electricity, Magnetism, Light, and Elementary Modern Physics, W. H. Freeman, ISBN 0-7167-0810-8
* Optical Physics (3rd ed.), Cambridge University Press, ISBN 0-5214-3631-1
===Textbooks and tutorials===
* [http://www.lightandmatter.com/area1book5.html Optics] — an open-source Optics textbook
* [http://www.optics2001.com Optics2001] — Optics library and community
===Societies===
* [http://www.myeos.org European Optical Society]
* [http://www.osa.org Optical Society of America]
* [http://www.osiindia.org Optical Society of India]
* [http://www.spie.org SPIE]
===Periodicals===
*[http://www.opfocus.org/ Optics & Photonics Focus]
*[http://www.nature.com/naturephotonics Nature Photonics]
*[http://www.photonics.com/ Photonics news]
[[Category: Physics]]
'''Optics''' is the [[science]] that describes the behavior and properties of [[light]] and the interaction of light with [[matter]]. Optics explains optical [[phenomena]]. The word ''optics'' comes from ''ὀπτική'', meaning ''appearance'' or ''look'' in ancient Greek).
Optics usually describes the behavior of visible, [[infrared]], and [[ultraviolet]] light; however because light is an [[electromagnetic wave]], similar phenomena occur in [[X-ray]]s, [[microwave]]s, [[radio]] waves, and other forms of [[electromagnetic radiation]] and analogous phenomena occur with [[charged particle]] beams. Optics can largely be regarded as a sub-field of [[electromagnetism]]. Some optical phenomena depend on the [[quantum]] nature of light relating some areas of optics to [[quantum mechanics]]. In practice, the vast majority of optical phenomena can be accounted for using the electromagnetic description of light, as described by [[Maxwell's equations]].
The field of optics has its own [[identity]], societies, and conferences. The pure science aspects of the field are often called optical science or optical [[physics]]. Applied optical sciences are often called optical engineering. Applications of optical engineering related specifically to illumination systems are called illumination engineering. Each of these disciplines tends to be quite different in its applications, technical skills, focus, and professional affiliations. More recent innovations in optical engineering are often categorized as [[photonics]] or [[optoelectronics]]. The boundaries between these fields and "optics" are often unclear, and the terms are used differently in different parts of the world and in different areas of industry.
Because of the wide application of the science of "light" to real-world applications, the areas of optical science and optical engineering tend to be very cross-disciplinary. Optical science is a part of many related disciplines including electrical engineering, physics, psychology, medicine (particularly [[ophthalmology]] and [[optometry]]), and others. Additionally, the most complete description of optical behavior, as known to physics, is unnecessarily complicated for most problems, so particular simplified models are used. These limited models adequately describe subsets of optical phenomena while ignoring behavior irrelevant and/or undetectable to the system of interest.
== Classical optics ==
Before [[quantum optics]] became important, optics consisted mainly of the application of classical electromagnetism and its [[high frequency approximation]]s to light. Classical optics divides into two main branches: geometric optics and [[physical optics]].
''Geometric optics'', or ''ray optics'', describes [[light]] propagation in terms of "rays". Rays are bent at the interface between two dissimilar media, and may be curved in a [[medium]] in which the refractive index is a function of position. The "ray" in geometric optics is an abstract object, or "instrument," which is perpendicular to the wavefronts of the actual optical waves. Geometric optics provides rules for propagating these rays through an optical system, which indicates how the actual wavefront will propagate. This is a significant simplification of optics, and fails to account for many important optical effects such as [[diffraction]] and [[polarization]]. It is a good approximation, however, when the wavelength is very small compared with the size of structures with which the light interacts. Geometric optics can be used to describe the geometrical aspects of imaging, including optical aberrations.
Geometric optics is often simplified even further by making the paraxial approximation, or "small angle approximation." The mathematical behavior then becomes linear, allowing optical components and systems to be described by simple matrices. This leads to the techniques of [[Gaussian optics]] and ''paraxial raytracing'', which are used to find first-order properties of optical systems, such as approximate image and object positions and magnifications.
Gaussian beam propagation is an expansion of paraxial optics that provides a more accurate model of coherent radiation like [[laser]] beams. While still using the paraxial approximation, this technique partially accounts for diffraction, allowing accurate calculations of the rate at which a laser beam expands with distance, and the minimum size to which the beam can be focused. Gaussian beam propagation thus bridges the gap between geometric and physical optics.
''Physical optics'' or [[wave optics]] builds on [[Huygens's principle]] and models the propagation of complex wavefronts through optical systems, including both the amplitude and the phase of the wave. This technique, which is usually applied numerically on a computer, can account for diffraction, interference, and polarization effects, as well as other complex effects. Approximations are still generally used, however, so this is not a full electromagnetic wave theory model of the propagation of light. Such a full model is much more computationally demanding, but can be used to solve small-scale problems that require this more accurate treatment.
== Everyday optics ==
Optics is part of everyday life. [[Rainbow]]s and [[mirage]]s are examples of optical [[phenomena]]. Many people benefit from eyeglasses or contact lenses, and optics are used in many consumer goods including cameras. Superimposition of periodic structures, for example transparent tissues with a grid structure, produces shapes known as [[moiré pattern]]s. Superimposition of periodic transparent patterns comprising parallel opaque lines or curves produces [[line moiré]] patterns.
== References ==
* Optics (4th ed.) Pearson Education, ISBN 0-8053-8566-5}}
* Physics for Scientists and Engineers (6th ed.) ISBN 0-534-40842-7
* Physics for Scientists and Engineers: Electricity, Magnetism, Light, and Elementary Modern Physics, W. H. Freeman, ISBN 0-7167-0810-8
* Optical Physics (3rd ed.), Cambridge University Press, ISBN 0-5214-3631-1
===Textbooks and tutorials===
* [http://www.lightandmatter.com/area1book5.html Optics] — an open-source Optics textbook
* [http://www.optics2001.com Optics2001] — Optics library and community
===Societies===
* [http://www.myeos.org European Optical Society]
* [http://www.osa.org Optical Society of America]
* [http://www.osiindia.org Optical Society of India]
* [http://www.spie.org SPIE]
===Periodicals===
*[http://www.opfocus.org/ Optics & Photonics Focus]
*[http://www.nature.com/naturephotonics Nature Photonics]
*[http://www.photonics.com/ Photonics news]
[[Category: Physics]]
