Optical frequency comb profilometry for large volume metrology

An optical profilometer composed of an optical frequency comb source, a single pixel camera, and an optoelectronic interferometer in radio frequecny range have been developed toward large volume metrology. The optical profilometer allows us to measure an object with a large depth much more than a light wavelength without any 2 pi phase ambiguity. The wide dynamic range is achieved with high stability of the optical frequency comb and the simultaneous multi-single-frequency operation. The single pixel camera is used for two-dimensional imaging without a mechanical scanning and the compressive sensing technique reduces the number of measurements. A surface profilometry for an object with a depth of several centimeters to a meter is demonstrated.