發(fā)布時(shí)間：2018-04-01 00:08

  本文選題：表面等離激元　切入點(diǎn)：U型金屬開口諧振環(huán)　出處：《淮北師范大學(xué)》2015年碩士論文

【摘要】：表面等離極化激元（SPPs）是一種沿著金屬和介質(zhì)之間的界面?zhèn)鞑サ�，由自由電子和電磁場相互作用產(chǎn)生的電子疏密波。它具有一系列的獨(dú)特光學(xué)性質(zhì)，例如局域電場增強(qiáng)，對電磁波的亞波長束縛，非線性增強(qiáng)等等。由于spp沿著金屬和介質(zhì)之間的界面?zhèn)鞑�，在金屬和介質(zhì)上縱向傳播的時(shí)候SPPs會呈指數(shù)衰減，因此，設(shè)計(jì)合適的金屬微結(jié)構(gòu)可實(shí)現(xiàn)對電磁波的調(diào)控。因其獨(dú)特的性能而被廣泛應(yīng)用于增強(qiáng)透射，負(fù)折射率材料，，超分辨率成像，生物傳感等方面。隨著超構(gòu)材料的加工和制備技術(shù)以及理論數(shù)值模擬分析手段的發(fā)展，越來越多的亞波長等離激元器件得到理論上的分析和實(shí)驗(yàn)上的驗(yàn)證。和傳統(tǒng)的，受到衍射極限限制的光學(xué)器件相比，等離激元器件在尺寸上可以達(dá)到亞波長的微納量級。在這些器件中，對表面等離激元波起到束縛和引導(dǎo)作用的是各種類型的波導(dǎo)，例如金屬納米陣列結(jié)構(gòu)，矩形槽波導(dǎo)，異質(zhì)結(jié)構(gòu)波導(dǎo)，V型槽波導(dǎo)，MIM波導(dǎo)等。在眾多波導(dǎo)中，MIM波導(dǎo)由于更好的束縛效果，模式尺寸小，傳輸損耗小和易于加工等優(yōu)點(diǎn)而得到了眾人廣泛的研究，理論上研究MIM波導(dǎo)的傳輸特性以及對其進(jìn)行調(diào)控具有重要意義。本文設(shè)計(jì)了基于MIM波導(dǎo)的周期型微納光學(xué)器件，通過數(shù)值分析的方法來討論這些結(jié)構(gòu)的電磁波傳播特性。 本文的主要工作和研究成果可以簡單歸結(jié)如下： 1、首先在MIM波導(dǎo)中加入單個(gè)U型開口金屬諧振環(huán)，研究金屬開口環(huán)和波導(dǎo)的各參數(shù)對結(jié)構(gòu)的透光性造成的影響，經(jīng)過探究發(fā)現(xiàn)，波導(dǎo)的共振波長隨著開口金屬諧振環(huán)臂長增大而呈現(xiàn)紅移現(xiàn)象；若增寬MIM波導(dǎo)，則波導(dǎo)中的共振趨于一個(gè)恒定的共振。 2、在波導(dǎo)中再次加入一個(gè)諧振環(huán)形成一字排列雙諧振環(huán)結(jié)構(gòu)。經(jīng)過數(shù)值分析，發(fā)現(xiàn)結(jié)構(gòu)中兩耦合共振會呈現(xiàn)出對稱模式和反對稱模式。隨著兩個(gè)諧振環(huán)間距逐漸增大，兩個(gè)透射谷逐漸重合在一起，直至形成一個(gè)透射谷。 3、將結(jié)構(gòu)做成周期排列的U型金屬開口環(huán)，發(fā)現(xiàn)周期型MIM波導(dǎo)的透射光譜呈現(xiàn)出了兩個(gè)帶隙，隨后我們探究了波導(dǎo)各參數(shù)對帶隙的影響：減小諧振環(huán)的排列周期可以使布拉格帶隙向短波長藍(lán)移；若增加諧振環(huán)的臂長，兩個(gè)透射禁帶會呈現(xiàn)一同向短波長藍(lán)移的性質(zhì)；增大MIM波導(dǎo)的寬度可以使兩個(gè)帶隙的寬度變窄。 4、隨后我們針對周期型MIM波導(dǎo)進(jìn)行了改變，做成了一大一小雙U型諧振環(huán)排列的周期結(jié)構(gòu)。通過對結(jié)構(gòu)的透射光譜分析，我們發(fā)現(xiàn)：在該結(jié)構(gòu)中也出現(xiàn)了雙帶隙，局域共振帶隙會隨著長U型諧振環(huán)的臂長增長而向長波長紅移；改變短U型諧振環(huán)的底部寬度可以使左側(cè)帶隙的線寬變寬，并使兩個(gè)帶隙共同出現(xiàn)了藍(lán)移現(xiàn)象；改變波導(dǎo)中的空氣介質(zhì)寬度會使兩個(gè)帶隙向高頻波段略微移動，同時(shí)縮短帶隙寬度。 5、最后設(shè)計(jì)了一種濾波器，可以通過調(diào)節(jié)豎直空氣波導(dǎo)的位置來調(diào)節(jié)結(jié)構(gòu)在1400nm波段的透光性能，也可通過改變空氣波導(dǎo)的長度來調(diào)節(jié)該濾波器的透射極小位置。 通過對以上結(jié)構(gòu)的分析，希望可以對以后的二維亞波長金屬微納器件的設(shè)計(jì)提供參考。
[Abstract]:This paper designs a kind of periodic micro - nano optical device based on MIM waveguide , which is widely used in enhancing transmission , negative refractive index material , super - resolution imaging and biosensing .

The main work and research results of this paper can be summarized as follows :

1 . Firstly , a single U - shaped open metal resonant ring is added to MIM waveguide to study the influence of the parameters of metal opening ring and waveguide on the light transmission of the structure , and it is found that the resonant wavelength of the waveguide exhibits a red shift phenomenon with the increase of the arm length of the opening metal resonant ring ;
If the MIM waveguide is widened , resonance in the waveguide tends to be a constant resonance .

2 . A resonant ring is added to the waveguide to form a double resonant ring structure . After numerical analysis , two coupling resonances in the structure are found to exhibit a symmetric mode and an anti - symmetric mode . As the spacing of the two resonant rings gradually increases , the two transmission valleys are gradually brought together until a transmission valley is formed .

3 . It is found that the transmission spectrum of the periodic MIM waveguide shows two band gaps , and then we investigate the influence of the parameters of the waveguide on the band gap : to reduce the arrangement period of the resonant ring , the Bragg band gap can be shifted to the short wavelength blue shift ;
If the arm length of the resonant ring is increased , the two transmission forbidden bands will show the properties of the blue shift with the short wavelength together ;
increasing the width of the mim waveguide may narrow the width of the two band gaps .

4 . The periodic structure of a small double U - shaped resonant ring is formed by changing the periodic MIM waveguide . Through the transmission spectrum analysis of the structure , we have found that in this structure , a double band gap is also present , and the local resonance band gap will shift to the long wavelength red with the increase of the arm length of the long U - shaped resonant ring ;
changing the width of the bottom of the short U - shaped resonant ring can widen the line width of the left side band gap and cause the blue shift phenomenon to be common in the two band gaps ;
changing the width of the air medium in the waveguide causes the two band gaps to move slightly toward the high frequency band while reducing the band gap width .

5 . Finally , a filter is designed , which can adjust the transmission energy of the structure in the 1400 nm wavelength band by adjusting the position of the vertical air waveguide , and the transmission minimum position of the filter can be adjusted by changing the length of the air waveguide .

Through the analysis of the above structure , it is hoped that the design of the later two - dimensional sub - wavelength metal micro - nano device can be referenced .

【學(xué)位授予單位】：淮北師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN252

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 Amnon Yariv;黃進(jìn)初;;導(dǎo)波光學(xué)[J];世界科學(xué)譯刊;1979年09期

本文編號：1693072