局域性表面電漿與單光子光源

Localized surface plasma and single photon source

莊雅雯(Ya-Wen Chuang)

指導教授 ： 褚志崧

國立清華大學/理學院/物理學系/碩士(2014年)

摘要

為了有效利用單光子光源，我們希望利用鍍上金屬薄膜的矽奈米柱陣列，設計出單光子波導，以局域性表面電漿傳遞電磁場。我們觀測了不同奈米柱直徑、不同奈米柱間距的陣列其反射光譜，藉此探討幾何結構對局域性表面電漿共振頻率的影響。此外，也嘗試以一道雷射激發一個量子點，藉此量子點的自發性輻射產生單光子。
實驗皆在室溫下進行，我們利用電子束微影的方式，蝕刻矽晶片，每一個奈米柱的直徑大約為100奈米至600奈米，陣列的大小從2微米至2毫米。鍍在奈米柱上的金屬為銀或金。在單光子光源實驗，我們使用波長為405奈米的脈衝雷射，量子點為放光波長585或705奈米的羧基化硒化鎘/硫化鋅量子點。
未來將探討不同奈米柱陣列形狀與單光子光源的交互作用，以及在波導兩端各放置一個量子點，以其中一個量子點作為光源，激發另一端的量子點。前者可應用於提高單光子光源的使用效率，後者則可應用於量子資訊的傳遞及儲存、糾纏雙光子的產生。

關鍵字

局域性表面電漿 ； 單光子 ； 波導 ； 奈米柱陣列 ； 反射光譜 ； 量子點 ； 共焦顯微鏡

並列摘要

In order to effectively use single photon sources, we designed waveguides for single photons. These waveguides were nano-scale array structures of metal-coated silicon nanorods and allowed the transport of electromagnetic field with localized surface plasma. By observing the reflectance spectra of different array structures, we investigated the influence of geometrical structures on the resonant enhancement of localized surface plasma. In addition, we managed to build a single photon source by focusing a pulsed laser to excite single quantum dots.
Experiments were conducted at room temperature. The arrays of silicon nanorods were constructed on silicon wafers by electron beam lithography. The diameter of each nanorod was 100nm ~ 600 nm and the size of each array was 2μm ~ 2mm. After the arrays were fabricated, silver or gold thin films were deposited on the surfaces either by electron beam evaporation or sputtering. In the setup of single photon source, we used a 405nm picosecond pulsed diode laser and carboxyl CdSe/ZnS quantum dots with emission maxima near 705nm.
In order to effectively use single photon sources, we designed waveguides for single photons. These waveguides were nano-scale array structures of metal-coated silicon nanorods and allowed the transport of electromagnetic field with localized surface plasma. By observing the reflectance spectra of different array structures, we investigated the influence of geometrical structures on the resonant enhancement of localized surface plasma. In addition, we managed to build a single photon source by focusing a pulsed laser to excite single quantum dots.
Experiments were conducted at room temperature. The arrays of silicon nanorods were constructed on silicon wafers by electron beam lithography. The diameter of each nanorod was 100nm ~ 600 nm and the size of each array was 2μm ~ 2mm. After the arrays were fabricated, silver or gold thin films were deposited on the surfaces either by electron beam evaporation or sputtering. In the setup of single photon source, we used a 405nm picosecond pulsed diode laser and carboxyl CdSe/ZnS quantum dots with emission maxima near 705nm.
In the future, we will study the interaction between the single photon source and different nano-scale array structures of nanorods. We will also investigate the effective interaction between two single photons that will be generated at opposite ends of one waveguide. The former can be applied to efficient use of single photon source; on the other hand, the latter is useful in quantum teleportation, quantum information storage and the generation of entangled biphotons.

並列關鍵字

localized surface plasma ； single photon ； waveguide ； nanorod array ； reflectance spectra ； quantum dot ； confocal microscopy

參考文獻

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