Airy beam
Encyclopedia
An Airy beam is a non-diffracting waveform which gives the appearance of curving as it travels.

Physical Description

A cross section of an Airy beam would reveal an area of principal intensity, with a series of adjacent, less luminous areas trailing off to infinity. In real applications, the beam is truncated so as to have a finite composition.

As the beam propagates, it does not diffract, i.e., does not spread out. The Airy beam also has the characteristic of freely accelerating. As it propagates, it bends so as to form a parabolic arc.

History

The term "Airy beam" derives from the Airy integral, developed in the 1830s by Sir George Biddell Airy to explain optical caustics such as those appearing in a rainbow.

The Airy waveform was first theorized in 1979 by M. V. Berry and N. L. Balz. They demonstrated a nonspreading Airy wave packet solution to the Schrödinger equation.

In 2007 researchers from the University of Central Florida were able to create and observe an Airy beam for the first time in both one- and two-dimensional configurations. The members of the team were Georgios Siviloglou, John Broky, Aristide Dogariu, and Demetrios Christodoulides.

Mathematical Description

The potential free Schrödinger equation
Schrödinger equation
The Schrödinger equation was formulated in 1926 by Austrian physicist Erwin Schrödinger. Used in physics , it is an equation that describes how the quantum state of a physical system changes in time....

:


Has the following Airy nondispersive solution:



where
  • is the airy function
    Airy function
    In the physical sciences, the Airy function Ai is a special function named after the British astronomer George Biddell Airy...

    .
  • is the electric field
    Electric field
    In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...

     envelope
  • represents a dimensionless traverse coordinate
  • is an arbitrary traverse scale
  • is a normalized propagation distance

Experimental Observation

Georgios Sivilioglou, et al. successfully fabricated an Airy beam in 2007. A beam with a Gaussian distribution was modulated by a spatial light modulator
Spatial light modulator
A spatial light modulator is an object that imposes some form of spatially-varying modulation on a beam of light. A simple example is an overhead projector transparency. Usually when the phrase SLM is used, it means that the transparency can be controlled by a computer. In the 1980s, large SLMs...

 to have an Airy distribution. The result was recorded by a CCD camera.

Applications

Researchers at the University of St. Andrews have used Airy beams to manipulate small particles, moving them along curves and around corners. This may find use in fields such as microfluidic engineering and cell biology.
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