Optocraft GmbH Optocraft GmbH

SHSLab: Universal tool for testing optics and lasers

The Shack-Hartmann wavefront sensor SHSLab is a powerful and comprehensive measurement solution for a multitude of optical applications, such as:

•    alignment of optical systems                     
•    measurement of imaging quality
•    surface shape measurement
•    laser beam characterization

The measurement principle captures wavefronts in one single shot, proving to be very fast and robust against external influences (e.g. vibrations). Through the combination of our excellent hardware (SHSCam) and software (SHSWorks), Optocraft’s SHSLab delivers superior accuracy, dynamic range and flexibility.

SHSLab comes in various models, covering applications with wavelength ranges from DUV to SWIR. Additionally, two SHSLab series are available for VIS/NIR ranges:

•    the high lateral resolution series features a micro lens pitch of 75µm enabling detection of localized phase defects
•    the broadband series offers highest wavefront measurement accuracy from 355nm to 1064nm at 130µm micro lens pitch


History and principle

In 1904, Johannes Hartmann published a technique for measuring objectives by using a metal mask with holes in it. The so-called Hartmann-screen test was born. It took until 1971 when Roland Shack improved the technique for applications in astronomy and space by making the principle more light efficient, using an array of micro lenses instead of holes.

SHSLab uses this geometric-optical Shack-Hartmann principle to measure wavefronts. A micro lens array transforms the local direction of beams into an array of focal spots on a camera. The deviation of these spots from their reference positions is calculated and finally the wavefront is reconstructed via numerical integration.