Axicon

Single axicons are usually used to generate an annular light distribution which is laterally constant along the optical axis over a certain range.

This special feature results from the generation of (non-diffracting) Bessel-like beams with properties mainly determined by the Axicon angle α.

The use of reflection rather than transmission improves the damage threshold, chromatic aberration, and group velocity dispersion compared to conventional axicons.

In research at Physikalisch-Chemisches-Institut, Heidelberg, Germany, axicon lenses have been used in laser diagnostics of mechanical properties of thin films and solids by surface-wave spectroscopy.

The laser pulse generates concentric surface acoustic waves, with amplitude that reaches a maximum in the center of the ring.

Their goal is to determine the effects of axicons on the Fourier distribution of random binary data spectrum of a spatial light modulator (SLM).

An article published by the research team at St. Andrews University in the UK in the Sept. 12 issue of Nature describes axicon use in optical tweezers, which are commonly used for manipulating microscopic particles such as cells and colloids.