Frequency modulated multiple wavelength parallel phase shift interferometry

A system for performing multiple wavelength phase shift interferometry (PSI), the system comprising:

• a) at least one light source, wherein all light sources together provide N beams of monochromatic light at N distinct wavelengths, wherein N≥2;
• b) components configured to modulate each of the N monochromatic light beams with a different carrier frequency;
• c) beam combining optics that combine the N monochromatic light beams into a combined light beam comprising the N wavelengths;
• d) an interferometer;
• e) at least one detector configured to detect all N wavelengths in the combined light beam output signal of the interferometer;
• f) at least one frequency domain demodulation unit configured to separate the interferometric signal output by the at least one detector into N signals, each containing information related to a different one of the wavelengths;
• g) phase modulation optics configured to produce M different specific phase shifts for all N wavelengths;
• and
• h) a processor and display unit comprising software algorithms and processing, memory, and display components configured to process M×N signals to extract phase information for optical path difference calculations and phase unwrapping.