2002 Fiscal Year Final Research Report Summary
An investigation of optical absorptions by periodic structures on cuticles of insects
| Project/Area Number |
13650023
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | KUMAMOTO NATIONAL COLLEGE OF TECHNOLOGY |
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Principal Investigator |
MATSUDA Toyonori KUMAMOTO NATIONAL COLLEGE OF TECHNOLOGY, DEPARTMENT OF INFORMATION & COMMUNICATION ENGINEERING, PROFESSOR, 情報通信工学科, 教授 (00157322)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIYAMA Eiji KUMAMOTO NATIONAL COLLEGE OF TECHNOLOGY, DEPARTMENT OF ELECTRONICS ENGINEERING, ASSOCIATE PROFESSOR, 電子工学科, 助教授 (00237752)
ITOH Hideo NATIONAL INSTITUTE OF AIST, CYBER ASSIST RESEARCH CENTER, LEADER, サイバーアシスト研究センター, デバイスグループリーダー主任研究員
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| Project Period (FY) |
2001 – 2002
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| Keywords | Periodic structures / Photonic crystal / Resonance absorption / Moth eye effect / Diffraction / Anti-reflection / Computer electromagnetism / Nano-technology |
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| Research Abstract |
The aim of this project is to investigate absorption, of light by periodic structures that exist on cuticles of insects. In the term of project, we have carried on the following studies.
1. Microscopic observation of insect corneas It has been reported that the front surface of corneas of a certain night moth is covered with minute nipples, which is much smaller than a wavelength of visible right and arranged in hexagonal array (Acta Physiological Scandinavia Vol.63. P.19). We observed corneas of numerous insects through a scanning electron microscope and found that some butterflies of Morphidae or Lycaenidae also have the nipple array on the surface of their corneas likewise a night moth. The shape of the cornea nipples of the butterflies is a circular cylinder and its diameter and height (amplitude), respectively, are about 0.1 and 0.2 micrometer. The center-to-center spacing of the nipples is also about 0.2 micrometer. It should be noted that the corneas could be considered as periodic structures of the nipples array.
2. Computer simulation We suppose that the optical functions of the insect corneas nipples may be associated with those periodic structures that are familiar with optical devices. We therefore constructed a periodic structure model of the nipples array on the basis of the microscopic observation. We have developed a numerical algorithm for analyzing diffraction of light from the periodic structures model. We evaluate reflectance and transmittance of the periodic structure models over the visible region from computer simulation. The algorithm can be also applicable to the numerical analysis of resonance absorptions of light by periodic structures.
3. Experiment We have investigated a measurement of reflectance and transmittance at the minute region of insect corneas by the microspectrophotmetric experiment. We also measured refractive indices of corneas by the immersion method.
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