塔姆電漿極化子於連續域內束縛態的研究

Tunable Bound states in the continuum with Tamm Plasmon Polaritons

吳秉儒(Bing-Ru Wu)

指導教授 ： 陳國平

國立交通大學/光電學院/光電系統研究所/碩士(2019年)

摘要

塔姆電漿極化子(TPP)是一種能將電場侷限在布拉格反射鏡與金屬薄膜之交界面的能態，並且無論是在正向或斜向(TE or TM 偏振)入射下都能激發。許多TPP的應用在傳感器或濾波片上，但是其共振並不能隨時地調控品質因子，加上品質因子是有限的，目前最多提升到十的三次方左右。本篇論文實驗一套系統，利用TPP結構以及非等向性材料(液晶)，並藉由轉動方位角(φ，入射光之電場偏振方向與液晶之導軸產生的夾角)來調控共振波長以及品質因子，從有限到無限大的品質因子都能實現，此現象叫做「連續域內的塔姆電漿極化子之束縛態」。由於非等向性的材料特性，可以將能量由TE與TM偏振互相轉換，意思是TPP共振在TE偏振，卻要由TM偏振下才能觀察的到。故我們將由布魯斯特角從DBR的基板端入射，並在此角度下轉動φ角在TM偏振下觀察TPP共振。當轉動φ角時，此共振變成準連續域內的塔姆電漿極化子之束縛態，其品質因子將由φ角決定。

關鍵字

塔姆電漿極化子 ； 非等向性材料 ； 連續域內的束縛態

並列摘要

Tamm plasma-polariton (TPP) resonance is a confined state at the interface between a distributed-Bragg-reflector (DBR) and a metal layer. Generally, the TPP can be excited by normal illumination and TE- (TM-) polarization. TPP devices are not easy to dynamically tune the Q-factor after the sample is fabricated. Here, we experimentally demonstrate a special class of resonances between DBR and a metal film, which can tune the Q-factor from finite to infinity – that is called “Tamm plasmon-polariton bound states in the continuum” (TPP-BIC). Because the anisotropic material is inserted into the structure, the TPP energy was released into TM-wave. Then we can freely rotate the incident light beam along with the Brewster angle cone to transform TPP-BIC to quasi-TPP-BIC. The azimuthal angle ϕ between the incidence plane and the anisotropic layer optical axis governs the Q factor of quasi-TPP-BIC.

並列關鍵字

Tamm plasmon polariton ； anisotropic material ； bound states in the continuum

參考文獻

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