Axicons - Highly precise from asphericon
In contrast to aspheric lenses, the shape of an axicon resembles a cone. The conical shape of the axicon generates a ring-shaped beam profile. The diameter of the ring beam depends on the axicon angle and decreases as the distance between the axicon and image plane grows. The ring width remains constant.
The Axicon is primarily used in the field of beam shaping and in various laser applications. A particular use is also the generation of non-diffractive Bessel-like beams. An area with almost constant intensity distribution, the length of which is defined by the angle and diameter of the axicon, is of interest here. Bessel beams are non-diffractive and ideal for applications in medicine, research, in measuring technology and for adjustments. Specifically, they find use e.g. in optical tweezers and in light sheet fluorescence microscopy.
In combination with other axicons or lenses, various beam profiles can be generated, such as collimated ring beams and variable ring-shaped focal points.
The optical effect in combination with a|BeamExpander, a lens or a second axicon is shown below.
1. The illumination of the axicon is optimized by combining it with a Beam Expander. This makes it possible to vary the length of the generated Bessel beam.
2. The diameter of the generated ring focus is defined by the focal length of the lens used. The generation of ring-shaped foci is used in material processing and in eye surgery, for example.
3. A collimated ring-shaped beam is generated by combining two axicons. The diameter of the beam changes with the distance between both elements.
4. This setup enables the focal width of an asphere to be reduced, whereby focusing below the diffraction limit is possible. This is made possible by the ring-shaped illumination of the asphere.
5. The setup shown is suitable to improve the focus quality of a spherical lens. Through what is known as zonal decompensation, the ring-shaped illumination of individual zones of the lens, effects of spherical aberration are eliminated and focusing is thus improved.
6. This setup is used to generate variable ring foci. By moving the second axicon, the diameter of the ring focus can be adjusted.
With the aid of specially developed mounts, our axicons can be oriented precisely to facilitate adjustment and achieve optimal imaging results. What’s more, mounted axicons, like all mounted lenses from asphericon, can easily be screwed to other elements using a metric fine thread. Learn more about the benefits of asphericons mounted lenses.
Based on your individual specifications, our optical designers develop the right axicon in terms of diameter, center thickness, angle and surface precision. Thanks to the latest production and measuring technology, a high level of precision is guaranteed.
Do you require axicons with outstanding precision dimensions and directly from stock?
Visit our Webshop and order conveniently online. Here you can find a wide range of precision-polished axicons in the diameters 25.4 mm and 50.8 mm. Order before 12 pm (CET) and your axicon will be shipped within 24 hours.
|Customized Axicons*||StockOptics Axicons|
|Diameter||1-420 mm||25.4 / 50.8 mm|
|Diameter Tolerance||+/- 0.03 mm||+/- 0.1 mm|
|RMS irregularities (RMSi)||40 nm||≤70 nm|
|Surface imperfections (Scratch/Dig)||20-10||40-20|
|Coating||Customer specific||4 standard-coatings|
|Laser damage threshold||NA||12 J/cm², 100 Hz, 6 ns, 532 nm**|
|Measurement (optional)||Full-surface interferometric||Full-surface interferometric|
|Delivery time||From 3-4 weeks||From 1 day|
* Best-fit-specifications | **100 Hz, 6ns, 532 nm