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Custom Freeform Optics

Freeform optics have the ability to transform the way optical systems are developed and push the boundaries of optical performance. Avantier creates unique freeform optics for cutting-edge applications in industry, defense, research, and medicine. Avantier specializes in Custom Freeform Optics Design and Manufacturing Solutions for Imaging, catering to both single prototypes and bulk production orders.

A freeform optic is described as having at least one surface that lacks translational or rotational symmetry about any axes normal to the mean plane. In reality, this implies that freeform systems are not limited by symmetry restrictions.

Freeform Optic.

Freeform Optic. Image Credit: Avantier Inc.

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Understanding Freeform Optics

Freeform optics are optical components that lack translational or rotational symmetry. These components have surfaces specified by general XY polynomials and more degrees of freedom than standard spherical optics.

A freeform optical surface has no constraints on its shape, whereas a conventional optical surface is rotationally symmetric. This flexibility gives distinct advantages in terms of improving optical performance while reducing device size.

However, producing freeform optical surfaces is more difficult; common techniques such as normal grinding and polishing are inadequate. Instead, specialized procedures such as single-point diamond turning are used to manufacture these components.

Metals, plastics, germanium (Ge), calcium fluoride (CaF2), magnesium fluoride (MgF2), zinc selenide (ZnSe), zinc sulfide (ZnS), gallium arsenide (GaAs), and silicon (Si) can all be utilized to create freeform optical components.


Since freeform optics minimize many of the frequent aberrations that affect conventional optics, they are often regarded as the optic of choice in certain scenarios. Using freeform optics can sometimes make a function that would be impossible with just spheres and aspheres functionally feasible. Among the specific advantages that many optical designers see in freeform optics are:

  • Advanced beam shaping
  • Lower number of optical elements in assemblies
  • Smaller, lighter, and more compact optical systems

Manufacturing Processes

Freeform optical production presents unique challenges since these optics are not rotationally symmetric and are not built with reference to the sphere that is the foundation of most conventional optics. Freeform optics cannot be shaped or polished using conventional methods, but it is possible to manufacture any required freeform, thanks to cutting-edge computer numerical control (CNC) optical grinding technology.

Usually, the process of creating a freeform optic starts with an optical blank being roughed out using grinding equipment that combines ultraprecise single-point diamond turning with CNC technology. Once the surface is established in CAM software, the tool produces a rough draft of the freeform surface by following computer instructions.

A ball tool with a CNC control is then used to grind the freeform surface both finely and roughly. Throughout the procedure, the new optic is taken out of the machine multiple times, and the profile is meticulously measured to identify any shape problems. The next grinding stages rectify these errors.

After the fine grinding of the freeform optic is completed, the piece is finished with a sub-aperture polishing process, and the optical surfaces are subjected to various metrology checks to verify they match all necessary specifications. Avantier employs surface profilers, interferometers, and computer-generated holograms to ensure that everything is correct.

Depending on the substrate, certain freeform optics are also manufactured via precision molding, followed by CNC-powered fine polishing. Metals, plastics, germanium (Ge), calcium fluoride (CaF2), magnesium fluoride (MgF2), zinc selenide (ZnSe), zinc sulfide (ZnS), gallium arsenide (GaAs), silicon (Si), and other materials have been suggested as freeform lens/mirror substrates.

Avantier is delighted to be a leading manufacturer of specialized freeform optics for imaging. Avantier optical engineers and designers are at the forefront of this emerging sector and possess the skills required to bring the ideas to reality.

Whether Avantier has extensive freeform optics designs for the required optic or merely a basic list of necessary attributes, they can work with users to provide the unique freeform optics they require.  Whether the user needs a single prototype or bulk production for industrial applications, Avantier can work with them to meet their goals.

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