近赤外分光用電磁駆動型2軸傾斜MEMSグレーティング

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This paper describes design and fabrication of electromagnetically driven dual-axis tilting MEMS-grating, and evaluation for low coherent near infrared spectroscopy. At first, we have investigated fabrication of laminar grating using EB lithography of UV photoresist and dry etching of silicon. In consequence, the laminar gratings of 0.6 - 2.0μm pitches were fabricated successfully. Second, we fabricated electromagnetically driven MEMS-grating which can tilt to dual-axis. Primary axis is used for spectroscopy, and the secondary axis is used for optical axis alignment. As the results of evaluation, primary and secondary DC tilting angles were 0.40°/mA and 0.39°/mA, respectively. And then, primary and secondary resonant frequencies (Q-factor) were 217Hz (Q36) and 172Hz (Q25), respectively. Finally, we constructed Fourier domain fiber interferometer whose sample arm was 2m in length. As setting optical length difference to be 180μm, the interference spectrum in wavelength range of 1400-1700nm was observed in less than 25ms by MEMS-GR, and a Fourier and axis transformed peak was acquired at 50dB.