Laser Interferometer

A laser interferometer, uses a split laser source beam to compare a test surface against a high-quality, “perfect” reference surface with sub-nanometer resolution. For machine tool metrology, a laser interferometer is used to map the errors of the slide ways (straightness, perpendicularity, pitch, yaw, and roll of each axis).

The most common measurement mode for a laser interferometer is Phase-Shifting Interferometry (PSI), which is used to measure very smooth surfaces such as polished optics. The test beam can be expanded or compacted to measure surfaces from a few millimeters to meters in diameter.