Aspherical lenses & mirrors

Opto-TL manufactures aspherical optics using Nanoform 200 diamond turning machine (USA) from the following materials:

  • Optical ceramics (ZnSe, ZnS, MgF2)
  • Optical crystals (Ge, Si, CaF2)
  • Metals (aluminum and copper alloys, nickel and brass)
  • Plastic

It is possible to process axially symmetric and non-axially symmetric surfaces, Fresnel lenses and rasters, as well as surfaces whose shape is described by power polynomials (freeform). The maximum deviation of the aspherical surface from the best fit sphere can reach several millimeters. Surface control is carried out directly on the machine using an UltraComp profilometer with a sensitivity of at least 10 nm (Fig. 1). The diameter of the processed surface is up to 200 mm.

Achievable parameters for processing the optical surface of products:

  • roughness of the polished optical surface - Ra 3-5 nm. (Fig. 2)
  • optical accuracy (P-V) - λ / 2, where λ = 633 nm. (Fig. 3)


Fig. 1 Surface profile.


Fig.2 Roughness measured with an interferometer-profilometer.


Fig.3 Surface interferogram, measured with an Opto-TL interferometer.

The use of such aspherical surfaces makes it possible to obtain optical systems with unique properties with minimal dimensions and to save expensive infrared materials by reducing the number of optical elements, which is one of the most innovative directions in optical technology.

Surface with diffractive elements

A good example is the possibility of manufacturing single hybrid lenses from germanium (instead of lenses made of two different materials with different dispersion), combining an aspherical surface with diffractive elements and providing achromatization of the system in the 8-14 μm region.

With the help of diamond turning, so-called "flat" lenses are made - plane-parallel plates with a diffractive structure that work like lenses, which leads to a significant reduction in the cost and weight of infrared lenses.

Reducing the size/weight characteristics while maintaining or even improving image quality due to the use of aspherical components is very important for infrared lenses, which are widely used in the space and aviation industries.

We also manufacture metal (aluminum alloy, copper and brass) aspherical mirrors that are used in many telescopic systems.

The Opto-Technological Laboratory proposes to redesign your lens without aspherics to a new design using aspherical and/or diffractive surfaces with the subsequent manufacture of such products.