German, Two Americans Share Nobel Physics Prize for Work on Quantum Optics. (October 5, 2005)

    It seems fitting that on the centenary of Einstein's annos mirabilis the 2005 Nobel Prize for physics should be awarded to three researchers who have pioneered the interrelationships between the wave and particle views of light and laid the foundation for the field of "quantum optics."

Harvard University theoretical physicist Roy Glauber received half the prize for mapping out the conceptual connection between assemblages of individual photons and classical waves of light while two experimental physicists, John Hall of the University of Colorado, JILA; National Institute of Standards and Technology Boulder, Colorado and  Theodor Hänsch of the Max-Planck-Institut für Quantenoptik
Garching and the  Ludwig-Maximilians-Universität Munich were awarded the other half for developing exquisitely precise techniques to manipulate laser light, which is a quantum-mechanical torrent of photons.

The statement from the Swedish Academy reads in part:

If a receiver or a detector is to register light, it must be able to absorb the radiation energy and forward the signal. This energy occurs in packets called quanta and a hundred years ago Einstein was able to show how the absorption of a quantum (a photon) leads to the release of a photoelectron. It is these indirect photoelectrons that are registered in the apparatuses when photons are absorbed.

 

Thus light exhibits a double nature – it can be considered both as waves and as a stream of particles. Roy Glauber has established the basis of Quantum Optics, in which quantum theory encompasses the field of optics. He could explain the fundamental differences between hot sources of light such as light bulbs, with a mixture of frequencies and phases, and lasers which give a specific frequency and phase.

 

The important contributions by John Hall and Theodor Hänsch have made it possible to measure frequencies with an accuracy of fifteen digits. Lasers with extremely sharp colours can now be constructed and with the frequency comb technique precise readings can be made of light of all colours. This technique makes it possible to carry out studies of, for example, the stability of the constants of nature over time and to develop extremely accurate clocks and improved GPS technology.

A more detailed discussion of the work for which the prise has been awarded can be found at  http://nobelprize.org/physics/laureates/2005/info.pdf.