Practical Tips Blog

4D Technology is the world's leader in the design and development of dynamic laser interferometers, dynamic optical surface roughness profilers and polarization cameras. In this blog we share practical information for accurately measuring optics and precision surfaces in challenging environments, despite vibration and environmental noise.

The highly polarized state of light scattered from the corona has been known since 1871. In 1905 Schwartzchild suggested that the polarization was produced from Thompson scattering of photons by free electrons trapped along magnetic field lines. This also led to the prediction that the polarization should have radial symmetry which was confirmed by Ney
4D Technology's NanoCam Sq surface profile helped the Keck Observatory overcome a challenge of phasing mirror segments in their segmented primary mirror
Phasing mirror segments is critical to accurate observations for many of the world’s largest telescopes, which employ segmented primary mirrors. In these instruments the primary mirror consists of many hexagonal segments, rather than a single, monolithic mirror. Using segments enables fabrication of larger primary mirrors. Segments are also easier to fabricate, transport, install, and maintain.
measure turbine blade edge defects with the 4D InSpec Surface Gauge
This video shows how the 4D InSpec Surface Gauge is used to measure turbine blade edge defects. The video walks through the quick process required to measure turbine blade edge scratches and pits. The presenter shows how focus, brightness and settings can affect measurement results. Click here to view the video.
4D InSpec Feature Analysis
This video shows how to use the 4D InSpec Surface Gauge Feature Analysis to measure surface defects on precision machined surfaces. The handheld, portable 4D InSpec can measure surface defects on large or complex surfaces. The Feature Analysis automatically locates all features in the field of view based on user-input criteria. It then presents them
measure corrosion
Use and environmental exposure inevitably lead to wear and corrosion of precision surfaces. Left unchecked corrosion can impede performance and can ultimately lead to component failure, sometimes with catastrophic results. Inspectors at repair and refurbishment facilities must be able to accurately measure corrosion and determine its severity in terms of pit depth and areal coverage.
4D InSpec measuring difficult to access areas of an aircraft engine fan disk and casing. By eliminating the need for replication measurement time is reduced from over an hour to less than a minute. Images courtesy StandardAero.
When measuring surface defects on large or complex components inspectors are faced with a dilemma. High resolution measurement systems are typically confined to a stand in a metrology lab, making them unable to measure large components. These system are also too susceptible to vibration to be used on a factory floor. Handheld depth gauges afford
Polarization images of Jupiter's poles
We are highlighting an exciting application of PolarCam technology today in the Practical Tips blog. In a recent astronomy application 4D Technology mounted a custom micropolarizer array to a thermoelectric cooled, 4 Megapixel Finger Lakes camera. Dmitry Vorobiev, an astrophysics PhD candidate at the Rochester Institute of Technology, installed the instrument in the 1-meter Cerro
NanoCam Sq Optical Surface Profiler
Measuring surface roughness on large optics has long been a challenge for manufacturers. Workstation based optical profilers do not have sufficient clearance to allow access to the central portions of larger components. Replication methods are messy and can potentially lead to damage of the optic. 4D’s NanoCam Sq Dynamic Surface Profiler was developed to measure
PolarCam Snapshot Micropolarizer Cameras provide image enhanceme​​nt for scene discrimination, remote sensing, industrial monitoring, autonomous vehicle vision and other applications. Taking advantage of that capability requires effective means to get the camera on location, which may be in cramped spaces, on uneven terrain or out of reach of a power source. A new series of
Plane-parallel optics are transparent components or systems with two or more parallel surfaces. Measuring them with an interferometer can be challenging, as all of the parallel surfaces can contribute interference fringes, making measurement extremely difficult or impossible. A new method makes it possible to exclude all but the surface of interest so that measurements can