Anamorphic Shaping of Laser Beams

29 May 2019

Anamorphic beam shaping optics are used to transform elliptical laser beams to a round shape - for example before coupling them to single mode optical fibers. Conversely, there are cases where originally round laser beams need to be transformed into an elliptical shape.

Schäfter+Kirchhoff uses two cylinder lenses acting in as a Galileo’s telescope in one direction. Due to the two-element design, it is possible to achieve excellent beam quality while using simple plano-convex and plano-concave cylinder lenses. Lens curvatures and glasses are selected so that the aberrations of both lenses cancel each other resulting in an overall diffraction limited design.

The anamorphic beam shaping optics series 5AN, is commercially available with aspect ratios ranging from 1:1.6 to 1:3 and for 390nm to 1800 nm. Typical applications are fiber coupling of beams from laser diodes or tapered amplifiers with aspect-ratios up to 1:3.

For two-dimensional magneto-optical traps (2D-MOTs) or in mirror magneto-optical traps, an elliptical shape of the laser is preferred. The laser beams used in these experiments often have a round shape, e.g., because they are originating from a singlemode fiber. In this case anamorphic beam shaping is used to generate the required elliptical beam shape.

Specialized fiber collimators are available which combine a fiber collimator, an anamorphic beam shaping optics 5AN and a beam expander to generate a large beam with elliptical cross-section.

An article on the details of anamorphic beam shaping can be found in PhotonicsViews 3/19 (WILEY-VCH Verlag)

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