09. August 2017

Aspheres offer the great advantage to accomplish monochromatic imaging tasks with one optical element where multiple lens elements would otherwise be needed.

Main advantages of aspheres are:

  • less spherical aberrations
  • larger aperture
  • less weight
  • less transmission loss
  • no internal ghosts

Another application of an asphere is beam shaping with respect to the intensity distribution or the phase. A typical conversion is the change of a Gaussian profile into a top-hat profile. For material processing, this form has the advantage of a more homogeneous removal of surface material, steeper borders between removal zone and surrounding material and a smaller heat induction zone.

The combination of high purity fused silica and low absorption coatings decreases thermal shift. The capability of Sill Optics MRF machines allows production of aspheres up to diameter 180mm. Measurement setup (interferometric wavefront test, tactile and optical 3D profilometry) enables us to ensure a surface quality of 0.2µm PV and 0.05µm RMSi. Even sagittal heights up to 21mm are measurable enabling the production and test of very steep radii at certain diameters.

Our range of products covers mounted and unmounted precision aspheres out of fused silica with focal lengths from 20 mm to 200mm, which are usable for focusing and collimation.

Special forms and customized versions are available on request.