Profilometer with sub-nanometer resolution for on-line measurement of fine optical surfaces.

The profilometer for on-line and non-contact measurement of the fine optical surfaces is described in this paper, which works on the principle of the differential interferometry with coaxial interference arms. The optical part of that is isolated and easy to install on the machine tools or the measuring machineries ea. This profilometer has excellent resistance to disturbance, especially to mechanical vibration, when the amplitude of vibration is about 300nm. So it still can be used to measure the micro-profile with sub-nanometer resolution. The vertical resolution of the profilometer is better than 0.05 nm rms. and need not add any condition or pretreatment