Glass capillaries based on a glass reflow into nano-trench for controlling light transmission


This paper reports the fabrication of Tempax glass capillaries based on a glass reflow into nano-trench for an optical modulator toward image sensing applications. The optical window consists of micrometer-order glass capillaries (porous solids) that can modulate the transmission light intensity by moving a liquid in and out of the porous solids. A high optical transmittance can be achieved due to refractive index matching when the liquid is penetrated into the porous solid. Otherwise, its light transmittance is low because of light reflection and scattering by air holes and capillary walls. The glass is completely filled into the nano-trench between silicon pillars under a high temperature process and assistance of enhancement of the surface wettability. Glass capillaries with depth of 8 μm, diameter of 1.2 μm, and the pitch of two capillaries of 2 μm have been achieved. The optical window integrated with an image sensor for an optical modulator is clearly demonstrated and a light modulation effect dependent on liquid penetration is observed.

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Part of this work was performed in the Micro/Nanomachining Research Education Center (MNC) of Tohoku University. This work was supported by Special Coordination Funds for Promoting Science and Technology, Formation of Innovation Center for Fusion of Advanced Technologies.

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Correspondence to Nguyen Van Toan.

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Van Toan, N., Sangu, S., Inomata, N. et al. Glass capillaries based on a glass reflow into nano-trench for controlling light transmission. Microsyst Technol 22, 2835–2840 (2016).

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  • Image Sensor
  • Glass Capillary
  • SiO2 Film
  • Microlens Array
  • Silicon Mold