SUSS MicroOptics’ Shack Hartman arrays for wavefront aberration detection
Shack Hartman wavefront sensors are used to measure the intensity distribution and phase distortion accurately and in real time. They are widely used in measurement and diagnostic instruments, and in optical systems to compensate for phase distortions.
A Shack Hartman wavefront sensor divides an incident wavefront into a number of beamlets. The microlenses in the array each provide a separate focus which, for an ideal planar incoming wavefront, form a highly periodic array of illuminated spots. Any aberrations in the wavefront displace the spots and by measuring this displacement the distortions of the incident wavefront can be determined.
Microlens arrays for Shack Hartman sensors tend to have small lens apertures to provide the high special resolution required for wavefront sensing. Microlenses with a short focal length are usually better for detecting highly distorted wavefronts whereas longer focal length microlenses are more suited to detecting smaller aberrations.