Superposition of two opposite "twisting" light modes (San Miguel)

Laser light that is in a superposition of two opposite "twisting" light modes. Twisted light has a screw-like (spiral) phase structure and carries orbital angular momentum, with which one can e.g. rotate particles around the optical axes. Theoretically, there is now upper limit on how strong the angular momentum of a single photon can be and even quantum feature like superposition or entanglement of more photons are preserved.

Superposition of two opposite "twisting" light modes
Gruppe Anton Zeilinger (Universit├Ąt Wien)