Classical and simple interferometer with plane-mirror, ball or hollow reflector:
Single laser beam with the same optical path for the reflected measuring beam.
Benefits:
- Best linearity
- Measurement also through small windows
- In case of using plane mirrors a lateral movement of the mirror or of the interferometer orthogonal to the measuring axis is possible.
- In case of using ball or hollow reflectors with high tilting invariance the adjustment of the interferometer is very easy. The measuring distance is increased compared to the mirror reflector.
Applications: Calibration of length measuring instruments, Multiple coordinate, measurements, e. g. on planar tables,Eccentricity and concentricity measurements
Highest-stable differential interferometer with plane mirror and cat-eye reflector:
Laser interferometer with minimum 2 beams – The path length difference of the beams detects the length.
Benefits:
- Differential measurement minimizes environmental effects.
Applications: Measurements with highest demands on stability, so for long-term measurements