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

Abstract

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.