非線性表面電漿超穎結構

Abstract

這幾十年來在非線性光學發展中，人們致力於了解在強場激發下電子所產生的非線性效應。已經有許多實際的非線性效應應用在不同領域之中，例如超快脈衝波、可調式非線性光源(光參振盪器)以及超解析成像技術等。在表面電漿共振現象中，光場會被侷域在次波長尺寸下並展現卓越光場增強的特性，這兩種特性可被應用在發展非線性奈米裝置上。在本論文中我們分別在時域和頻率域上探討直立式裂環共振器的非線性響應。藉由模擬分析證明了直立式裂環共振器可以在正向入射激發下產生兩種不同的非線性偏振態，並且可以被用來操縱非線性光的輻射方向。在本論文中我們也比較了裂環共振器以及直立式裂環共振器的非線性特性。為了更進一步瞭解直立式裂環共振器的非線性產生機制，多極模態分析也被用來檢驗各模態對非線性的貢獻。

In the past several decades, researches have devoted to understanding the responses of interaction between electrons under strong light excitation in nonlinear optics. There are a number of practical applications based on the concept of nonlinear optics, such as ultrafast pulse, tunable light source (Optical parametric oscillator), and super resolution imaging. Photonics plasmons with the characteristics of tight light confinement and significant light enhancement exhibit great potential for developing the practical nonlinear devices. In this dissertation, the nonlinearity of novel three-dimension structure, vertical split ring resonator (VSRR), is subsequently investigated both in time and frequency domain(time-averaged). We have demonstrated the additional access of VSRR provides significant enhancement to improve second harmonic generation (SHG) signal, generate dual nonlinear polarization states, as well as guide the nonlinear signal achieving nonlinear light manipulation. Comparisons of the nonlinear conversion efficiency between planer split ring resonator (SRR) and VSRR are discussed. The contribution of multipoles is also investigated for directly getting insight into underlying nonlinear conversion mechanism of VSRR.