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Schlieren Method: Some History. Robert Hooke Discovered “Schlieren Method” 1665 Used two candles and a convex lens Low quality instruments OK! August Toepler Used conventional Schlieren System Trying to find impurities in lenses More complicated system, better equipment.
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Schlieren Method: Some History • Robert Hooke • Discovered “Schlieren Method” 1665 • Used two candles and a convex lens • Low quality instruments OK! • August Toepler • Used conventional Schlieren System • Trying to find impurities in lenses • More complicated system, better equipment Although Schlieren looks and sounds like a German name, it is not the name of a scientist. The Schlieren method originated in Schlieren, Switzerland, and it has become an adjective describing the method itself.
Schlieren Method: How It Works Simple Schlieren Setup • Produces image of an object • Deflection of light by refractive index gradient • Converging Lens • Knife Edge Blocks unwanted light • Lens places image on screen
Schlieren Optics • Point source of light illuminates an object or image. • Image is focused on a knife edge. • When index of refraction of the medium surrounding the object or image changes • Image focal point will be perturbed • Diffracted rays will interfere Perturbed focal point
References • http://en.wikipedia.org/wiki/Schlieren • http://www.abb.com/global/ • http://www.lav.ethz.ch/research/projects/actual_projects/Experimentals/EHCCI/index • http://www.rit.edu/~andpph/photofile-b/usch • Hect, Eugene and Alfred Zajac. Optics. 3rd ed. New York: Addison Wesley Publishing Company, 1997. • C:\Documents and Settings\AdvancedLab-II\Optics\Newport-Optics\2004S-Newport-Burns-etal.ppt