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位相シフト干渉法は干渉する2光波間に一定の位相シフトを導入したときの3つ以上の干渉縞画像から被検の位相分布を百分の1波長以上の精度で導出する方法で、高精度位相計測の強力な手段として注目されている。しかし、その計測精度は位相シフトに大きく依存し、高価なピエゾ素子が必要な上、キャリブレーションもしばしばと問題となる。この問題を解決するため、試料のない直線的な干渉縞領域を用いた高精度初期位相推定法を提案し、コンピュータシミュレーションでその有効性を確かめた。, Phase-shifting interferometry is a very powerful tool for high-precision measurement both in industry and in scientific research. However, the measurement accuracy is strictly affected by the phase shift values that introduced to form interferograms. Usually an expensive equipment such as a piezoelectric device is used, and a pre-calibration procedure is also needed. The authors propose a method to estimate the phase shift value of each interferogram from the intensity distribution. The usefulness of the proposed method was demonstrated by computer simulation.

光導波路や活きた生物細胞の高精度定量計測のために、我々は複プリズムやウォラストンプリズムの横移動を用いた共通光路位相シフト干渉顕微鏡を開発してきた。この方法では、交通光路の構造から、除振台なしでの干渉計測が可能や、非常に高い位相計測の安定性と再現性をゆする。本研究では、このような特徴を活かし、システム誤差や位相シフト誤差の低減法を提案し、サブナノの位相計測再現性を実現した。, Several techniques are presented for improving the phase measurement accuracy of the common-path phase-shifting interference microscope. Experimental results for elimination of the system phase error using a subtraction procedure is shown. The residual RMS phase error smaller as λ/1000 corresponding to 0.6nm was achieved. Experimental results for measuring the refractive index distribution of polarization-maintaining optical fibers are presented to demonstrate the usefulness of the method.

Surface-tension-driven flow of molten silicon was investigated under microgravity and on earth for liquid bridge configuration. In order to investigate instability structure in a molten silicon bridge, observed were temperature oscillation and its phase relationship using thermocouples, oscillation of a molten silicon bridge surface using phase shift interferometry, oscillation of melt/solid interface position oscillation and so on. Instability structure shows azimuthal wave number m, depending on an aspect ratio of a liquid bridge: Gamma = h(height)/r(radius). Surface-tension-driven-flow shows oxygen partial pressure dependence of an ambient atmosphere. This is due to oxygen partial pressure dependence of temperature coefficient of surface tension., 資料番号: AA0045947018, レポート番号: NAL SP-56