In electromagnetic wave propagation , the
knife-edge effect or
edge diffraction is a redirection by diffraction of a portion of the
Kaynak: Knife-edge effectThe Foucault
knife-edge test was described in 1858 by French physicist Léon Foucault to measure conic shapes of optical mirrors, with
Kaynak: Foucault knife-edge testThe equipment most amateurs use to test the shape of the mirrors, a Foucault
knife-edge test , is, like the tools used to create the
Kaynak: Amateur telescope makingFive definitions of the beam width are in common use: D4σ, 10/90 or 20/80
knife-edge, 1/e 2, FWHM, and D86. The beam width can be measured
Kaynak: Beam diameterKnife-edge width : Before the advent of the CCD beam profiler, the beam width was estimated using the
knife-edge technique. The technique is
Kaynak: Laser beam profiler called "Foucault
knife-edge test " allows the worker to tell if the mirror is perfectly spherical or has non-spherical deviation in its figure .
Kaynak: Léon FoucaultWhen a
knife-edge is used, the system is generally referred to as a schlieren system, which measures the first derivative of density in
Kaynak: Schlieren photographyIt also can be used to extract a 3-dimensional vascular network from the data from a
knife-edge scanning microscope at a significantly
Kaynak: Local maximum intensity projection