基於波導共振之手鏡超穎介面之研究;Research of chiral metasurface based on waveguide resonance

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/92449

Title:	基於波導共振之手鏡超穎介面之研究;Research of chiral metasurface based on waveguide resonance
Authors:	林易承;Lin, Yi-Cheng
Contributors:	光電科學與工程學系
Keywords:	波導;手性;超穎介面;波導模態共振;guidemode;chiral;metasurface;guide mode resonance
Date:	2023-08-16
Issue Date:	2024-09-19 15:52:29 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文將使用超表面來組成內在手性結構來對圓二色性進行研究探討，我們發現由奈米鰭柱組成的超表面會表現出 GMR 特性，而GMR的特點是在特定波長下會在波導結構內繞射並產生共振，在本研究中，我們通過改變奈米鰭柱的偏振光源、週期、旋轉角度、厚度和入射光角度來探索各方面的特徵，發現在垂直入射特定週期和厚度的奈米鰭柱下，左右圓偏振光的波長峰值會不同，進而形成圓二色性(Circular Dichroism, CD)。為了在可見光上使用，選擇了Nb2O5作為結構材料，SiO2作為基板，因其在可見光上有不錯的折射率而且低吸收，當光入射到結構和基板時，有助於形成GMR特性產生。此內在手性結構可以應用在可見光波段下，當光源垂直入射下擁有0.95的CD值，如果入射角在0到5度時，CD為0.95到0.77左右，這表明此結構在入射光量測誤差下，CD依然可以保持在不錯的數值。 ;This paper investigates circular dichroism (CD) using metasurfaces composed of intrinsic chiral structures,we found that metasurfaces composed of nano-fin arrays exhibit giant magneto-optical resonance (GMR) characteristics. GMR is known for its diffraction and resonant properties within the waveguide structure at specific wavelengths. In this study, we explore various aspects by manipulating the polarization source, period, rotation angle, thickness, and incident angle of the nano-fin arrays. We discovered that under specific periods and thicknesses of vertically incident nano-fin arrays, the wavelength peak values of left and right circularly polarized light differ, resulting in circular dichroism (CD). To enable operation in the visible light range, Nb2O5 was chosen as the structural material, and SiO2 was used as the substrate due to its favorable refractive index and low absorption in the visible light range. When light is incident on the structure and substrate, it helps in the generation of GMR characteristics. This intrinsic chiral structure can be applied in the visible light wavelength range. Under normal incidence, it exhibits a CD value of 0.95. When the incident angle ranges from 0 to 5 degrees, the CD value varies from approximately 0.95 to 0.77. This indicates that even considering measurement errors in incident light, the CD value can still be maintained at a satisfactory level.
Appears in Collections:	[Graduate Institute of Optics and Photonics] Electronic Thesis & Dissertation

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