In the traditional Hartmann test, a pinhole array is positioned in front of the optical system to be investigated. The corresponding 2D point cloud is depicted by the system on a CCD camera. As the pinhole distances on the substrate and the resulting point distances on the CCD are known, it is possible to determine aberrations introduced by the optical system. Shack-Hartmann wavefront sensors use microlenses instead of pinhole arrays. They are generally used in the characterisation of optical systems and in adaptive optics. In ophthalmology, the eyes are measured with a wavefront sensor before laser treatment (LASIK), allowing the areas to be treated to be defined.
Customers rely on the ‘Made by IMT’ quality both for Hartmann plates and for the microstructuring of supplied microlens arrays, onto which a metal coating needs to be applied in order to avoid interfering light.