Axicon lenses - Highly precise from asphericon
In contrast to aspheric lenses, the shape of an axicon resembles a cone. Due to the conical shape of the axicon lens so-called bessel beams, ring-shaped beam profiles, can be generated. 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 lens, 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 laser beam expander, a lens or a second axicon is shown below.
1. The illumination of the axicon lens is optimized by combining it with a laser 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.
Based on high-end technologies asphericon manufactures axicons with surface shape deviations (RMSi) of up to 0.04 µm. Together with our customers, we develop and produce suitable solutions from a large selection of optical glasses, from prototypes to series production. Take advantage of individual custom solutions,optical coatings or the innovative variety of stocked axicons from the StockOptics product line. The latter are available with surface deviations of RMSi ≤ 0.07 µm in our webshop.
In order to simplify alignment and achieve optimal imaging results, axicons from asphericon can also be precisely aligned using specially developed mounts. In addition, the mounted axicons, like all mounted optics from asphericon, can be easily screwed to other elements via a metric fine thread. Learn more about the benefits of asphericons mounted lenses.
Thanks to their conical shape, all axicons can be used in a wide variety of applications.
|Customized Axicons*||Stocked 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|
|Material||customer-specific (almost every type of glass, silica, |
germanium, silicon, IR lenses, zerodur)
|Mounting||customer-specific||available for selected lenses|
|Delivery time||from 3-4 weeks||from 1 day|
|Download Data Sheet||Webshop|
* Best-fit-specifications | **100 Hz, 6ns, 532 nm
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.