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Prisms are blocks of optical material with flat polished sides arranged
at precisely controlled angles to each other, which deflect, deviate and
rotate beams of light as well as dispersing their wavelengths. There are
many types of prism, each having a particular geometry to achieve the
reflections necessary to perform a specific task. Reflecting prisms may
invert, rotate, deviate or displace a beam. Dispersing prisms produce
spectral separation for spectroscopic applications or for tuning a laser
output.
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Prism Type
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Applications |
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Equilateral prism
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Dispersing prisms (also known as equilateral prisms) are used for
wavelength separation applications. A light ray is twice refracted
through the prism with a total deviation of qd. Deviation is a function
of refractive index, and hence wavelength. |
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Penta Prism
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Penta prism can deviate an incident beam without inverting or reversing
to 90 deg. The deviation angle of 90 deg is independent of any rotation
of the prism about an axis parallel to the line of intersection of the
two reflecting faces. It is commonly used in Plumb Level, Surveying,
Alignment, Range-finding and Optical Tooling. |
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Right Angle Prisms
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Right angle prism is deviating or deflecting a beam of light with 90° or
180°.It is often used in telescope, periscope and other optical system.
For example, two right-angle prisms can be cemented together at 90
orientation to form an image erector. Such an erector is used in many
binoculars. Righ angle prisms are also used as building blocks for
other optical components such as cubic beam splitters. |
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Dove Prism
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Dove prism has two applications. The main application is used as a
rotator. It can rotate an image but without deviating the beam. And when
the prism is rotated about the input parallel ray through some angle,
the image rotates through twice that angle. It is very important that
the application must be used with parallel or collimated beam and the
large square reflective surface should be kept very clean. Another
application is used as a retroreflector. For this application it perform
as a right-angle prism. |
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Roof Prism (Amici Prism)
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Roof prism is combined with a right angle prism and a totally internally
reflecting roof and they are attached by them largest square surfaces.
It can invert and reverse an image, also, deflect the image 90° .
Therefore, it is often used in terrestrial telescopes, viewing systems
and rangefinders. |
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