Volume 3 Issue 5, May 2007

Volume 3 Issue 5

All physicists know that light carries both linear and angular momentum. What is perhaps less well known, however, is that its angular momentum can be broken down into spin and orbital components. Spin angular momentum is associated with polarization, whereas orbital angular momentum arises from a more complex combination of the phase and amplitude profiles of an optical field. Although the spin momentum is the predominant property used in optical-based quantum information applications, orbital momentum is potentially more powerful for encoding and processing such information in high-dimensional quantum spaces. In this issue, Gabriel Molina-Terriza and colleagues review progress in the generation, understanding and use of the orbital angular momentum of light.

[Progress Article p305]


  • Editorial |

    As gatekeepers to the development of nuclear weapons, physicists have a right to a seat at the table in deciding what role these weapons have in a post-cold-war world.


  • Correspondence |

    • Jean-Baptiste Trebbia
    • , Gaël Varoquaux
    •  & Francesca Arcara


  • Commentary |

    The question of replacing the UK Trident submarines involves science, technology, national security and international policy. But before the vote, did parliament have access to crucial information? Did the Ministry of Defence?

    • Richard L. Garwin


Research Highlights

News and Views

  • News & Views |

    Transport measurements point to spontaneous formation of an array of local magnetic moments in a two-dimensional electron system tuned to low density.

    • Lindsay S. Moore
    •  & David Goldhaber-Gordon
  • News & Views |

    Experimental physicists study the strong force; string theorists try to calculate its effects. Together, they are finding common ground, where string theory can be applied to the physics of quark–gluon plasma.

    • Makoto Natsuume
  • News & Views |

    Scattering not only broadens the width of the optical transition between two levels but can enable optical gain and absorption to coexist — a fact that is unambiguously demonstrated by the observation of 'Bloch gain' in a quantum cascade laser.

    • Andreas Wacker
  • News & Views |

    Although it is over 100 years since Millikan showed that electric charge is quantized, it is only with the development of a new generation of charge pumps that this fact can be used to define the fundamental unit of electrical current, the ampere.

    • Per Delsing
  • News & Views |

    A unidirectional launch pad for electromagnetic surface waves may provide the missing link between conventional optics and future highly integrated photonic chips.

    • Stefan Maier