FREQUENCY MODULATED MULTIPLE WAVELENGTH PARALLEL PHASE SHIFT INTERFEROMETRY

摘要

Herein is provided a simplified method for performing multiple wavelength phase shift interferometry measurements that is implemented by modulating each of the monochromatic light sources with a different carrier frequency, combining them to a single beam, detecting all wavelengths simultaneously using the same detectors and separating them via Fourier analysis and demodulation of the data. This approach offers both a simplification to the optical system and reduces the duration of time required to perform the multiple wavelength measurement, based on a simple data extraction algorithm decoding the information for each wavelength. When combined with the parallel phase shift orthogonal polarization interferometric microscopy this method provides fast, stable, high precision 3D imaging and displacements sensing. Also disclosed are embodiments of optical systems designed to carry out the method.