Presentation Information
[9p-N402-3]Generation of Low-Coherence Dual-Combs Using PM Fiber Etalon and its application to 3D Profilometry
〇Satoshi Kanai1, Yuki Sekiguchi1, Kenta Arai1, Ryosuke Kuwayama1, Tatsutoshi Shioda1 (1.Saitama Univ.)
Keywords:
Optical Frequency Comb,Interferometry,Low-Coherence Light
To address the need for high-speed, high-precision 3D profilometry, we have proposed a low-coherence dual-comb spectroscopy (LC-DCS) system that overcomes the cost and complexity of conventional DCS. This paper presents a method for generating the requisite low-coherence optical combs (LC-OFCs) using a novel PM fiber etalon and reports its application to 3D shape measurement.
The key to LC-DCS is a precise, minute optical path length difference (OPD). Our etalon ingeniously provides this by cascading two PM fibers with their polarization axes rotated 90 degrees. This structure enables the flexible creation of a micron-order OPD (~7.6 µm), which is impractical with a single short fiber.
In our experiment, we used the etalon and a supercontinuum source to measure a 50 µm nominal step-height standard with a polarization-division Michelson interferometer. From the correlation peaks of interferograms, we simultaneously determined the step height to be 50.7 µm (RMSE 2.4 µm) and the surface tilt as 0.63 degrees. This result validates the method's powerful capability for accurate 3D characterization.
The key to LC-DCS is a precise, minute optical path length difference (OPD). Our etalon ingeniously provides this by cascading two PM fibers with their polarization axes rotated 90 degrees. This structure enables the flexible creation of a micron-order OPD (~7.6 µm), which is impractical with a single short fiber.
In our experiment, we used the etalon and a supercontinuum source to measure a 50 µm nominal step-height standard with a polarization-division Michelson interferometer. From the correlation peaks of interferograms, we simultaneously determined the step height to be 50.7 µm (RMSE 2.4 µm) and the surface tilt as 0.63 degrees. This result validates the method's powerful capability for accurate 3D characterization.