Polytec's TopMap devices are based on the principle of the white-light interferometer. In one arm of the interferometer, the test sample is securely positioned, in the other arm a reference mirror is located.
The interferometer set-up is moved relatively to the test sample at a constant velocity. Figure 1 shows a schematic view of the TopMap interferometer unit. A camera captures images of the test sample superimposed with the reference mirror. Interference only occurs if the optical path difference between the reference mirror and the corresponding points on the test sample is zero.
During this measurement run, the software detects interference on each pixel depending on the topography of the test sample. After traveling along the predefined distance, the topographical structure of the test sample is digitally available. The results can be evaluated using the TopMap software with numerous features. The export function and the automation interface allows other applications to process the topography data.
Fig. 1: Setup of a white light interferometer
|
