| 摘要 |
A laser interferometric apparatus for measuring a displacement of an object is disclosed, the apparatus comprising a laser source for producing a laser beam having a given intensity, a beam splitter for dividing the laser beam into a reference beam and an object beam to be directed to the object, thereby producing a scattered object beam being modulated according to the displacement of the object, interference means adapted to provide at least two electrical interference signals from the scattered object beam and the reference beam, the at least two electrical interference signals each comprising a wanted signal component indicative of the object displacement and an intensity noise component, and processing means for subtracting the at least two electrical interference signals, thereby generating an output signal, the output signal comprising substantially the wanted signal component alone, wherein the intensity noise is substantially rejected.
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