{{Short description|Optical phenomenon}} {{Distinguish|text = the typographic dagger (†), used to represent extinct species or languages}} {{no footnotes|date=October 2018}} thumb|right|An extinction cross photographed with a CCD camera using a green laser beam and a polarizer The '''extinction cross''' is an optical phenomenon that is seen when trying to extinguish a laser beam or non-planar white light using crossed polarizers. Ideally, crossed (90° rotated) polarizers block all light, because light that is polarized along the polarization axis of the first polarizer is perpendicular to the polarization axis of the second. When the beam is not perfectly collimated, however, a characteristic fringing pattern is produced.
==See also== *Polarization (waves)
==Further reading==
* [http://ruby.colorado.edu/~smyth/G30106.html Mineralogy notes 6] See "6.3.5. Review of Uniaxial Optical Properties" * [http://www.microscopyu.com/tutorials/java/dic/dicalignment/index.html Nikon MicroscopyU] See Figure 1a
{{Sci-stub}} Category:Polarization (waves) Category:Optical phenomena