蝴蝶結形週期性孔洞之異常穿透與可選擇波長多頻譜熱紅外線發射器之研究

The Studies of Extraordinary Transmission of Periodic Bowtie-shaped Aperture Array and the Wavelength-selective Multi-Spectral IR Thermal Emitters

黃紹宇(Shao-Yu Huang)

指導教授 ： 李嗣涔

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02860

摘要

本文在理論及實驗上研究蝴蝶結形週期性孔洞的異常穿透特性，實驗上發現二階的銀/矽模態之穿透強度大於一階的，而此現象可用三角形孔洞之尖角產生的磁場增強效應做解釋。藉由增加尖角距離、尖角角度以及金屬薄膜之厚度，此種二階模態的增強效應便會逐漸減弱。另一方面，平行四邊形金屬片陣列為上層之金屬/介電質/金屬結構的電漿子熱輻射發射器的特性也在研究範圍中，不同於正方形或長方形的金屬島嶼，平行四邊形中兩個主模態之極化方向決定於圖形的幾何結構，其中一個的極化接近於長對角線方向，另一個則在短邊共振。進一步，利用消波塊形狀為上層結構之電漿子熱輻射發射器可以在紅外線波段產生三個峰值，而這三個模態可粗略地用極化片選擇。藉由改變消波塊中每個長方形金屬島嶼之長度，可製作出所需波段之三峰值的紅外線熱輻射發射器。

關鍵字

表面電漿 ； 異常穿透 ； 熱輻射發射器

並列摘要

The extraordinary transmission through a silver film perforated with bowtie-shaped aperture array arranged in a rectangle lattice is investigated in theory and experiment. It is found that the second order Ag/Si modes have stronger transmission intensity than the fundamental one, which can be ascribed to the magnetic enhancement between the triangular tips. By increasing the tip separation, tip angle or the metallic film thickness, the enhancement effect of the second order modes vanishes gradually. In addition, the characteristics of the plasmonic thermal emitter (PTE) in metal/dielectric/metal (MIM) structure using parallelogram metallic islands as top layer have been studied. Different from square or rectangular metallic islands, two localized surface plasmon (LSP) modes are observed and their polarizations are dependent on the geometry of the pattern. One has the polarization close to the long diagonal while the other one resonant along the short side. Moreover, when using a block pattern as top structure in the PTE, three peaks can be observed in the emission spectra. These modes can be selected roughly by an external polarizer. By adjusting the lengths of the rectangles in the block pattern, an active IR source with the desired wavelengths can be fabricated.

並列關鍵字

Plasmonics ； Extraordinary transmission ； Thermal emitter

參考文獻

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