| Project/Area Number |
13650042
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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 optics/Quantum optical engineering
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
KIKUTA Hisao Graduate School of Engineering, Osaka Prefecture University, Lecturer, 工学研究科, 講師 (10214743)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Optical band-pass filter / Moth eve structure / Guided-mode resonant grating filter / Low sideband / Optical thin film / Subwavelength structured surface / Diffraction grating / Waveguide / フォトニック結晶 / 反射防止 / 共鳴反射 / 波長フィルター |
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| Research Abstract |
We proposed a new structure of guided-mode resonant grating (GMRG) filters with low sideband reflectance. This GMRG filter consists of a high-index thin film on an antireflective structured surface called "moth-eye structure". Since the high-index film undulates along the surface structure, the film acts as a modulated optical waveguide. An incident light wave satisfying a resonant condition is reflected by the GMRG filter, and nonresonant light waves pass through the filter. This GMRG filter is valid for reducing reflection of nonresonant light waves in a wide spectral range.
The resonant reflection of this new filter was investigated by numerical calculation based on an electromagnetic grating analysis. In the case of a triangular antireflective surface structure whose thickness is 2x greater than its period, the sideband reflectance for nonresonant light waves was lower than 0.5% for TM-polarized light in a wade range of wavelength.
We also fabricated a GMRG filter on an antireflective surface structure. A base substrate was a triangular surface structure of fused silica with a period of 333 nm and a height of 〜700 nm. TiO_2 thin film of 100 nm thick was spattered on the moth-eye surface. The refractive indices of the fused silica substrate and the TiO_2 thin film are 1.47 and 2.3. This GMRG filter occurs a resonant reflection at wavelength of 680 nrn with FWHM (full-wide at half maximum) of 0.7 nm. However, the sideband reflectance was lower than 4%.
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