Smart Processing of Micro Photonic Crystals for Terahertz Wave Control - Freeform Fabrication by Stereolithographic Technique -

Abstract:

Photonic crystals with periodically arranged structures of ceramics can reflect light or electromagnetic waves through Bragg diffraction and exhibit forbidden gaps in transmission spectra. We have successfully fabricated micro diamond crystals including twined lattices with plane defects to realize wavelength selections in terahertz frequency ranges. Novel smart processing composed of computer aided design, manufacturing and evaluation was established. The terahertz waves are expected to detect micro cracks in material surfaces and structural defects in electric circuits by fine wave interferences, and to analyze cancer cells in human skins and toxic bacteria in natural foods through high frequency excitations. In the fabrication processes using micro patterning stereo-lithography, the photo sensitive resin paste including alumina fine particles were spread on a glass substrate with 10 µm in layer thickness by moving a knife edge, and cross sectional images of ultra violet ray were exposed by using a digital micro mirror device with 2 µm in part accuracy. Through the layer stacking process, micrometer order structures were formed exactly. Dense ceramic components could be obtained through dewaxing and sintering heat treatments. The electromagnetic wave transmission spectra were measured by terahertz wave spectroscopy. The micro diamond lattices could form perfect photonic band gaps opining for all crystal directions. The introduced plane defects realized the wave select resonations. This resonation behavior was visualized and analyzed by finite difference time domain simulations.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 1925-1930
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.1925
• Online since: January 2012
• Authors: Soshu Kirihara, Noritoshi Ohta, Youhei Takinami, Satoko Tasakai
• Keywords: Alumina, Diamond Photonic Crystal, Micro-Stereolithography, Terahertz Waves

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