by Mike Zecchino
5.11.2009 ©4D Technology Corporation 4Sight is a trademark and Dynamic Interferometry is a registered trademark of 4D Technology Corporation
An overview of the techniques and configurations used to build dynamic interferometers and measurement results for a variety of space-based optical components
For over 20 years, 4D Technology has been a leader in innovative metrology products for measuring surface quality and surface defects on precision surfaces, as well as the surface and wavefront quality of optics. 4D’s patented Dynamic Interferometry® technology enables measurements in difficult
environments, where vibration, air turbulence or rapid motion have traditionally prevented
accurate measurement.
During that time, 4D interferometers have been used to assure the quality of some of science’s most challenging telescope projects, both terrestrial and in space. An early customer was NASA, which used several instruments to measure the James Webb Space Telescopes multi-mirror components, the alignment of those mirrors, and the supporting structure for them, both in air and in cryo- and vacuum-chamber tests.
Measuring Large Mirrors With Secondary and Tertiary Support Structures
Laser interferometry is a widely established method for measuring the shape and surface quality of large telescope mirrors. Dynamic Interferometry®, developed by 4D Technology Corporation, is an improved method in which all measurement data is acquired simultaneously, rather than over several frames and several hundred milliseconds. This technology enables measurement of large mirrors even in the presence of vibration and air turbulence, without expensive isolation equipment.
Challenges arise for interferometric measurements when the mirror or system under test is partially obscured by structural members…
Download this free case study from our partners 4D Technology, written by Mike Zecchio.
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