This article summarizes equations used in optics, including geometric optics, physical optics, radiometry, diffraction, and interferometry.
Definitions
Geometric optics (luminal rays)
General fundamental quantities
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Physical optics (EM luminal waves)
There are different forms of the Poynting vector, the most common are in terms of the E and B or E and H fields.
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Radiometry
right|275px|thumb|Visulization of flux through differential area and solid angle.
As always  \mathbf{\hat{n}} \,\!
is the unit normal to the incident surface A,  \mathrm{d} \mathbf{A} = \mathbf{\hat{n}}\mathrm{d}A \,\!, and  \mathbf{\hat{e}}_{\angle} \,\!
is a unit vector in the direction of incident flux on the area element, θ is the angle between them.
The factor  \mathbf{\hat{n}} \cdot \mathbf{\hat{e}}_{\angle} \mathrm{d}A = \mathbf{\hat{e}}_{\angle} \cdot \mathrm{d}\mathbf{A} = \cos \theta \mathrm{d}A \,\!
arises when the flux is not normal to the surface element, so the area normal to the flux is reduced.
For spectral quantities two definitions are in use to refer to the same quantity, in terms of frequency or wavelength.
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Equations
Luminal electromagnetic waves
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Geometric optics
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Subscripts 1 and 2 refer to initial and final optical media respectively.
These ratios are sometimes also used, following simply from other definitions of refractive index, wave phase velocity, and the luminal speed equation:
\frac{n_1}{n_2} = \frac{v_2}{v_1} = \frac{\lambda_2}{\lambda_1} = \sqrt{\frac{\epsilon_1 \mu_1}{\epsilon_2 \mu_2}} \,\!
where:
ε = permittivity of medium,
μ = permeability of medium,
λ = wavelength of light in medium,
v = speed of light in media.
</div> Polarization
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Diffraction and interference
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Astrophysics definitions
In astrophysics, L is used for luminosity (energy per unit time, equivalent to power) and F is used for energy flux (energy per unit time per unit area, equivalent to intensity in terms of area, not solid angle).
They are not new quantities, simply different names.
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See also
Defining equation (physics)
Defining equation (physical chemistry)
List of electromagnetism equations
List of equations in classical mechanics
List of equations in gravitation
List of equations in nuclear and particle physics
List of equations in quantum mechanics
List of equations in wave theory
List of relativistic equations
Sources
Further reading
Optics equations Optics Equations
