Combining phase images measured in the radio frequency and the optical frequency ranges

Phase images measured in the radio frequency (RF) and optical frequency (OF) ranges, whose difference was about 4×10⁵, were combined on the basis of a pattern matching method. RF phase imaging was implemented with an optical frequency-comb femtosecond laser and a single-pixel camera to measure a meter-order depth object with micrometer-order accuracy. OF phase imaging was implemented with an optical interferometer using a low-coherence femtosecond laser pulse to measure the profile with nanometer-order accuracy and high spatial resolution. Combining the images obtained from both phase measurement systems enabled profilometry of a large depth object with high lateral and axial resolutions.