Axicon Bessel Beam

Express 16 12688 12700 2008.

Axicon bessel beam.

They are typically generated from axicons. Bessel beams due to their non diffracting property are drawing attentions for different applications. Bessel beams are also self healing meaning that the beam can be partially obstructed. Special features and bessel beam shaping.

When converting a collimated beam into a ring the plano side of the axicon should face the collimated source. Single axicons are usually used to generate an annular light distribution which is laterally constant along the optical axis over a certain range. They are commonly used to create a beam with a bessel intensity profile or a conical non diverging beam. An ideal axicon with infinite tip does not exist and in practice an axicon comes with a rounded tip.

A par tic u lar use is also the gen er a tion of non dif frac tive bessel like beams. A bessel beam is a wave whose amplitude is described by a bessel function of the first kind. Here the bessel beam center exhibits the typical sub diffractive intensity spot with a full width at half maximum fhwm of 0 32λ and the first intensity mini mum at 0 26λ. Bessel beam generation from round tip axicon we model the generation of bessel beams with an axicon with a round tip and investigate how the round tip may influence the bessel beam evolution.

An area with almost constant intensity dis tri b u tion the length of which is defined by the angle and diameter of the axicon is of interest here. An axicon also known as a rotationally symmetric prism is a lens that features one conical surface and one plano surface. Axicon bessel beams are used in a variety of laser applications where the focus media is transparent at the laser wavelength. Bessel beam features of an axicon.

Unlike a gaussian beam which deteriorates over distance a bessel beam is non diffracting maintaining an unchanged transversal distribution as it propagates. This is in contrast to the usual behavior of light which spreads out after being focused down to a small spot. The bessel beam side lobes show an interfer ence pattern with a shallower radial intensity gradient than in the gaussian case. One such field is laser glass cutting often done with single mode ultrashort pulse lasers in the ir and green wavelengths.

This special feature results from the generation of non diffracting bessel like beams with properties mainly determined by the axicon angle α. Generating bessel beams for micro processing canunda axicon is an off axis reflective axicon that generates high quality bessel beams for glass processing with an ultra short pulse laser. Electromagnetic acoustic gravitational and matter waves can all be in the form of bessel beams. In this example we investigate the effect of the round tip on the generated bessel beams following the research work in o.

A true bessel beam is non diffractive. The axicon is primarily used in the field of beam shaping and in various laser ap pli ca tions.