18 May 2016 Laser beams with a ring-shaped profile are required in ophthalmology, laser welding, and the material ablation of thin films.
In order to produce this ring profile, often classic axicons are used: conical lenses and rotationally-symmetrical prisms. These elements convert a laser beam with a Gaussian profile into a Bessel beam. Axicons are very difficult to produce for very large or very small fan angles because in these cases the cones must either have a very shallow or very steep angle respectively; thus, an optimal ring profile generally cannot be achieved.
Holo/OR now manufacture diffractive optics with an axicon structure. These DOEs yield vastly superior results to the classic axicon. The ring profile remains close to perfect, irrespective of the fan angle, as the optic uses grating technology.
The versatile diffractive axicons are suitable for almost all lasers providing the M2<20, and are available on both fused silica and ZnSe. Furthermore, the element’s performance is independent of the input beam mode.
There are more than fifteen standard designs available with a peak-to-peak ring angle of 0.05° to 30°, with the option of custom designs upon request. | 
