奈米球及奈米線電漿子的電子能量損失譜之理論計算

Abstract

摘要 由於電漿子的高強度近場能突破光學繞射的極限，而成為發展奈米尺度下光學儀器的重要機制。為了能夠了解電漿子的特性，本論文將會利用模擬電子束激發奈米球與奈米線電漿子模式的方式來探討。也藉由改變電子束入射的速度快慢、位置與方向，以及考慮在不同材質與大小的金屬顆粒情形下，觀察各模式的變化，與對應的特徵能量的關係。而其中的Cherenkov radiative mode，是一種有趣的激發模式更是只有考慮電子相對論計算下才能觀測到的現象。除此之外，本論文的最後將會模擬計算的結果與電子束實驗的數據進行比較，並且統整與分析。

Since plasmons have strong near-fields, they can break the limit of optical diffraction and become an important mechanism for developments of optical instruments. In order to explore the characteristics of plasmons, in this thesis we simulate the plasmon modes in spherical and cylindrical nanomaterials excited by fast electron beams. In addition, the variations of mode eigenfrequencies as a function of incident electron speed, location, and direction were carefully studied. An exotic mode of Cherenkov radiation was also carefully investigated and cannot be tackled without the thorough relativistic consideration of the calculations. Comparison between electron-beam experiments and calculations were also briefly discussed.