In physics

Physics

Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

, coherence theory is the study of optical effects

Physical optics

In physics, physical optics, or wave optics, is the branch of optics which studies interference, diffraction, polarization, and other phenomena for which the ray approximation of geometric optics is not valid...

 arising from partially coherent

Coherence (physics)

In physics, coherence is a property of waves that enables stationary interference. More generally, coherence describes all properties of the correlation between physical quantities of a wave....

 light and radio sources. Partially coherent sources are sources where the coherence time

Coherence time

For an electromagnetic wave, the coherence time is the time over which a propagating wave may be considered coherent...

 or coherence length

Coherence length

In physics, coherence length is the propagation distance from a coherent source to a point where an electromagnetic wave maintains a specified degree of coherence. The significance is that interference will be strong within a coherence length of the source, but not beyond it...

 are limited by bandwidth, by thermal noise, or by other effect. Many aspects of modern coherence theory are studied in quantum optics

Quantum optics

Quantum optics is a field of research in physics, dealing with the application of quantum mechanics to phenomena involving light and its interactions with matter.- History of quantum optics :...

.

The theory of partial coherence was awoken in the 1930s due to work by P. H. van Cittert and Frits Zernike

Frits Zernike

Frits Zernike was a Dutch physicist and winner of the Nobel prize for physics in 1953 for his invention of the phase contrast microscope, an instrument that permits the study of internal cell structure without the need to stain and thus kill the cells....

.

Topics in coherence theory

• Visibility
  Interferometric visibility
  The interferometric visibility quantifies the contrast of interference in any system which has wave-like properties, such as optics, quantum mechanics, water waves, or electrical signals. Generally, two or more waves are combined and as the phase between them is changed The interferometric...
  
  
• Mutual coherence function
• Degree of coherence
• Self coherence function
• Coherence function
• General interference law
• Van Cittert–Zernike theorem
  Van Cittert–Zernike theorem
  The Van Cittert–Zernike theorem is a formula in coherence theory that states that under certain conditions the Fourier transform of the mutual coherence function of a distant, incoherent source is equal to its complex visibility. This implies that the wavefront from an incoherent source will...
  
  
• Michelson stellar interferometer
  Michelson stellar interferometer
  The Michelson stellar interferometer is one of the earliest astronomical interferometers built and used. The interferometer was proposed by Albert Michelson in 1890, following a suggestion by Hippolyte Fizeau....
  
  
• Correlation interferometry
• Hanbury–Brown and Twiss effect
• Phase-contrast microscope
• Pseudothermal light
• Englert–Greenberger duality relation
• Coherence Collapse

See also

• Nonclassical light
  Nonclassical light
  Nonclassical light is any state of light that cannot be described using classical electromagnetism; its characteristics are described by the quantised electromagnetic field and quantum mechanics...
  
  
• Optical coherence tomography
  Optical coherence tomography
  Optical coherence tomography is an optical signal acquisition and processing method. It captures micrometer-resolution, three-dimensional images from within optical scattering media . Optical coherence tomography is an interferometric technique, typically employing near-infrared light...
  
  
• Coherence theory of truth
  Coherence theory of truth
  Coherence theory of truth regards truth as coherence with some specified set of sentences, propositions or beliefs. There is no single coherence theory of truth, but rather an assortment of perspectives that are commonly collected under this title...