title: Poincaré sphere
text: # Poincaré sphere
  
  Poincaré sphere may refer to:
  
  * Poincaré sphere (optics), a graphical tool for visualizing different types of polarized light
     * Bloch sphere, a related tool for representing states of a two-level quantum mechanical system
  * Poincaré homology sphere, in mathematics, an example of a homology sphere
  