Axially symmetrically polarized beams

2. Methods of producing axially symmetric beams

Axially symmetric beams are not produced by ordinary laser systems, but require specialized equipment. There are three ways of producing axially symmetric beams:
   1.The combination of several lasers with a high degree of precision.
   2.Transmission through special filters.
   3.Construction of specialized laser systems.
The first method is very difficult because of the high degree of precision required. The second method can be achieved by the use of an LCD, or a photonic crystal. However the simplest method is the third.

The laser system consists of a cavity; 2 mirrors, gain media and a pump source (lower left). The laser beam is emitted from the half mirror when it is appropriately placed.

Simply by substituting a photonic crystal element for the half mirror, it is possible to produce a stable radially or azimuthally polarized beam. Using the autocloning technology it is possible to fabricate elements with an circular structure. Using the same substrate (with an annular pattern), we can produce elements with radial or azimuthal transmittance axes. Thus both radial and circular beams can be produced.
The reflectance can be precisely controlled by the number of layers deposited, thus the reflectivity can be adjusted per requirements. Furthermore as autocloned photonic crystals are composed exclusively of inorganic materials, they exhibit the high damage thresholds and heat resistance required by ultra fast and high power laser applications. For the first time by using our elements it is possible to produce stable axially polarized beams efficiently and simply.

Our line of azimuthally and radially symmetric polarization products for YAG lasers (1064nm) will become available from July 2, 2007. For information regarding photonic crystal technology, please refer to the photonic crystal technology page.