Research On The Micro And Nano Measurement System Based On The Principle Of Interferometry

A novel fiber-optic interferometric measurement system, which is based on the principle of interferometry and is suitable for distant measurement for micro-nano surface, is proposed. The system includes two optical fiber interferometers. One of the optical fiber interferometers is used for sensing the measurand remotely; and the other one is used to demodulate the measurand. By employing fiber Bragg gratings as in-fiber reflective mirrors, the demodulating optical fiber interferometer works in both modes of low coherence interferometry and high coherence interferometry. The signal of high coherence interferometry is used for measuring the measurand precisely, and the signal of low coherence interferometry is used for determining the amplitude of the measurand. Absolute measurement has been realized and the measurement range will never be limited to be half a-wavelengh.For an optical point scanning measurement system for the measurement of3D micro-nano surface, the measurement speed is very low and two dimension scanning action is needed. We presented a novel optical line-scanning measurement system for the measurement of micro-nano surface profile. The broadband light emitted from an amplified spontaneous emission (ASE) is dispersed into a piece of fan-shaped light by a blazed grating. The piece of fan-shaped light is collimated into a piece of parallel light and then is used to scan the measured surface. Different wavelength is reflected by the different measured point of the surface. The reflected wavelength is interfered with the reference light. Each pixel of a line array CCD detects the interferometric signal from the corresponding measured point of the surface. The height of the measured point of the surface will be obtained by processing the data from CCD by a matlab software program. The3D surface will be realized by the optical-line scanning the surface in one dimension.