What is the practical limit of surface topography on an interferometer?
Can the interferometer measure a three-dimensional surface?
The practical limit of surface topography that can be measured by an interferometer depends on several factors, including the type of interferometer, the wavelength of light used, the quality of the optical components, and the nature of the surface being measured.
Interferometers are highly precise instruments used for measuring small displacements, including surface topography. They work by splitting a light beam, sending one part to interact with the surface under study (test surface) and the other part to a reference surface. The two beams are then recombined, creating an interference pattern that can be analyzed to determine the surface characteristics.
Interferometers are commonly used to measure two-dimensional surface topography (height maps) with high precision. To measure a three-dimensional surface, additional techniques are often employed to combine multiple 2D measurements or use 3D scanning approaches.
Two common methods to measure 3D surface topography are:
While interferometers can provide accurate 3D measurements in many cases, they do have limitations. For instance, measuring large and highly complex surfaces with steep slopes or discontinuities can be challenging due to restricted measurement range and potential difficulties in data stitching. In such cases, other techniques like structured light 3D scanners or confocal microscopy may be more suitable.
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