Question

Which of the following is true about resolution in two frequency laser interferometer?

(a) Straightness resolution –  90 nm

(b) Angular resolution – 3 arc seconds

(c) Flatness resolution – 2 nm

(d) Linear resolution – 1 nm

I had been asked this question in class test.

I would like to ask this question from Laser Inspection in chapter Machine Vision Systems of Engineering Metrology

Answer 1

Right answer is (d) Linear resolution – 1 nm

The best I can explain: The advantage of two frequency laser interferometer technique is that system does not depend upon the beam intensity and provides high sensitivity, it is also independent of noise due to air turbulence. The linear resolution by two frequency laser interferometer technique is 1 nm, angular resolution is 0.03 arc seconds and straightness resolution is 40 nm.