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Aspheric lens

 

asphericon is setting standards in the production of high-precision optics

These days, industrial and research facilities require unprecedented precision for targeted activities involving light. Numerous applications were unthinkable even just 25 years ago. asphericon has specialized in the production and machining of high-precision aspheric lenses. Premium quality and repeatability are cornerstones of the products we develop for you – from individual aspheric lenses to mounted optics and complex systems.

Advantages of an aspheric lens

Correction of spherical aberration by using an asphere Spherical lenses inevitably produce imaging errors, so-called spherical aberrations (as shown in figure on the right). An aspheric lens is rotationally symmetric, with one or more non-spherical surfaces that differ from the shape of a sphere. These properties allow the correction of aberrations. Thanks to the latest manufacturing technologies, we are also able to manufacture aspheric lenses in series with the highest precision.

Multi-stage manufacturing process

asphericon is specialized in manufacturing of aspheric lenses through grinding and polishing. A so-called blank is subjected to various work steps:

  • Grinding for shaping,
  • Polishing the ground aspheric lens,
  • Measurement to proof shape and surface,
  • Measurement and machining to achieve a high-end finish

Blanks are pre-shaped elements and the base for further processing of aspheric lenses. During the first step, the blank is ground to its desired shape. Various grinding tools are used for this complex process.

Secondly, the polishing process is an important part in the production of an aspheric lens. The surface is machined, step by step to achieve the desired requirements (e.g. the surface form deviation). Polishing is achieved through abrasive and chemical removal of material by using very fine grain polishing compounds. A final polished lens has a bright surface without pores and deep cracks, as well as the desired accuracy and surface quality.

The subsequent measurement serves to verify the shape and surface to determine and correct any existing deviations. An aspheric lens can be measured tactile and contactless depending on processing state and accuracy.

The ION-Finish™ technology, aspheric lensThe high-end finishing is the final processing step, for even more precise surfaces. The ION-Finish™ technology developed by asphericon and the Magnetorheological Finishing-Technology® (MRF), enable accuracies of λ/600 RMS on plane surfaces – even in series production. In addition, we offer asphericon Ångström-Polishing, a process for aspherical surfaces with roughness values of 5 Å (Rq according to ISO 10110), e.g. for applications with high laser power.

Application examples

The use of an aspheric lens is mainly based on its advantages compared to a spherical lens. The biggest benefit is the correction of aberrations resulting in better imaging properties.

Telescopes today, for example, are almost always aspherical, especially those with larger diameters. Aspheric elements are also used in zoom lenses. Not only the system size is reduced but also the imaging quality is increased compared to applications with spherical lenses.

It is possible to use aspherical lenses directly in space or to observe the stars from earth. The Sentinel-4 satellite, for example, contains aspheric optics from asphericon in its spectrometers. For use in space, the optics do not only need excellent optical properties, but also have to withstand extreme environmental conditions. More about Sentinel-4 can be found here.

Another field of application is laser beam shaping, such as the generation of Top-Hat beam profiles. In a beam shaping system with two aspheric lenses for Top-Hat light distribution the first lens is used to redistribute the incoming laser beams (Gaussian distribution) in such a way that a homogeneous intensity distribution is achieved at a certain distance. The second lens collimates the beam and as a result, the characteristic Top-Hat distribution is created. These aspheric applications are of interest in material processing (e.g. cutting of metal) and also in medical applications (e.g. ophthalmology). A detailed description of laser beam shaping with aspheric lenses and other application examples can be found in our blog.

A relatively new application for aspheric lenses on the market is the field of metrology. Their use can significantly reduce the total number of lenses used in a Fizeau transmission sphere and increases the measuring range. Another advantage: the transmission sphere is also significantly lighter thanks to the use of fewer lenses. Further information on the use of aspheric lenses in transmission spheres can be found on the a|FizeriC page, our aspheric Fizeau lens.

Aspheric lenses made by asphericon

Find out more about further advantages of our optical elements in the following.

 

Aspheric lens
at the highest level

asphericon manufactures your desired products at the highest technological level. The worldwide unique control technology of our CNC machines guarantees a perfectly finished aspheric lens according to your requirements in almost any shape and size. We manufacture with the highest technological standards and achieve precision even at atomic levels.

Surface optimisation
with precision

An aspheric lens “made by asphericon” has optimized functional surfaces with unique properties, you won’t find anywhere else. Using various manufacturing processes, we are able to produce extremely precise surfaces that are guaranteed to meet your requirements.

Despite the technical challenges an aspheric lens presents to manufacturers, our asphericon ION-FinishTM and Magnetorheological Finishing-Technology® surpass international standards in high-end finishing.

Know-how &
Economy

Benefit from our expertise gathered in numerous projects while partnering with renowned scientific and industrial institutions. We can implement your individual challenging solutions precisely.

For small as well as large order quantities we work with the proven asphericon precision. At the same time, we work efficiently and economically, making your project a complete success!

Discover the possibilities we offer in-house for your aspheric lenses:

Behind each asphericon optic, stands a team of well-trained experts. Their experience expands day by day from demands of customer projects. Suitable for your application you choose from a variety of different shapes and materials for all wavelengths, and we take care of the implementation.

asphärischeLinse
asphericon also manufactures high-precision axicons, aspheric cylinders, mirrors and reflectors as well as mounted optics, beam expanders, beam shapers and Fizeau transmission spheres.