研究テーマ：低コヒーレンス干渉計測法による物体形状とスペクトルの同時計測方の研究 Research theme: Study of simultaneous measurement system of both tomography and spectroscopy using a low-coherence interferometry
Abstract: The simultaneous measurement system for the tomography and spectroscopy of materials are widely needed in various fields. Low-coherence interferometry is used for tomography because high spatial resolution, approximately submicrometers or micrometers, can be obtained only with a compact optical system, which implements an interferometer and a low-coherence light. The tomography obtained by a low-coherence interferometry is capable of measuring inner structure of materials as non-invasive and non-contact method. On the other hand, Fourier transform spectroscopy is well-known as a powerful technique for composition analysis. Its configuration is similar to low-coherence interferometry in time-domain. Fourier transform spectroscopy is commonly used compared with dispersive spectrometers because of Fellgett advantage, Jacquinot advantage, and so on. The two methods, low-coherence interferometry and Fourier transform spectroscopy, are similar systems because they consist of an interferometer and a low-coherence light. Thus, it is worthwhile trying to develop a measuring system that can obtain both tomograpic image and spectrum of a sample. In this paper, we propose a novel technique, which can obtain both tomography and accurate complex electric field spectra of a sample simultaneously. In addition, a spectral calibration method is proposed to obtain accurate spectra. The proposed technique and spectral calibration method were experimentally demonstrated with a transparent sample and several kinds of colored sample with planar interfaces. The refractive index, its dispersion, and power reflectance spectrum were determined from the calibrated electric field spectrum.