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physical object > artifact > device > instrument > optical device > wavefront modifier

wavefront modifier
subject			fact

wavefront modifier	has wavefront modification shape, polarization or wavelength
	has definition A device which modifies the wavefront shape, polarization or wavelength
	is a kind of optical device
instrument	has operator
artifact	has creator
	has creation date
	has purpose
	has owner
physical object	has location or center of gravity
	has angular momentum
	has mass
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of wavefront modifier :

• aspheric (1 kind, 5 facts) - An optical surface with departures in shape from a perfect sphere in order to cancel optical imperfections or aberrations.
• atmospheric dispersion corrector (3 facts) - An optical device usually comprising two thin prisms which can rotate to compensate for the elongation of a star image caused by the wavelength dependence of the refractive index of air.
• focal reducer (3 facts) - An optical component or system for changing the image scale of a telescope to achieve a better match between the seeing disk and the pixel size. See optical matching.
• lens (4 kinds, 13 facts)
• mirror (14 kinds, 26 facts)
• Nicol prism (3 facts) - A device made from a split crystal of Iceland spar with which plane-polarized light can be detected.
• objective (3 facts) - The primary mirror of a reflecting telescope (or the primary lens of a refractor).
• optical fibre (4 facts) - A long, thin strand of glass capable of excellent transmission of light over large distances., Glass and transparent plastics can be made into a very thin wire or fiber. Typical dimensions are 10-50 µm. If a ray enters one end of a fiber at the appropriate angle, it will undergo total internal reflection and travel down the fiber without much loss through the sides.
• optical matching (3 facts) - The use of lenses or other optical devices to match the size of the image of the seeing disk, as it appears in the focal plane of the telescope, to the physical size of the CCD pixels. If the telescope yields 10 arcseconds per millimeter and the seeing is 1 arcsecond then the image is 0.1 mm in size. But a typical CCD pixel is 0.022 mm, five times smaller.
• Pockels cell (3 facts) - An electro-optic crystal used as a reversible waveplate by applying alternately high positive and negative voltage.
• spectrograph dispersing element (9 kinds, 27 facts) - The part of a spectrograph which disperses the light into component colors

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