本文選題：等離子體超材料 + 電磁吸收器��； 參考：《深圳大學(xué)》2015年碩士論文

【摘要】：等離子體超材料是一種具有金屬-電介質(zhì)微納結(jié)構(gòu)的人工電磁材料,具有自然材料難以獲得的特異電磁性質(zhì)。近十年來,等離子體超材料在科研界引起了的廣泛興趣以及進(jìn)行了大量的研究。在等離子體超材料眾多的應(yīng)用中,其中一個(gè)重要的領(lǐng)域就是超材料電磁吸收器。早期的吸收器依賴于材料本身的吸收特性,不可避免地導(dǎo)致了體積龐大,吸收效率低的缺點(diǎn)。等離子體超材料則是基于金屬納米結(jié)構(gòu)激發(fā)等離子體共振對入射光進(jìn)行完美吸收(100%吸收率)。這種吸收器具有深度亞波長尺度,完美吸收以及諧振頻率可調(diào)等一系列優(yōu)點(diǎn),在諸如熱輻射發(fā)射器,傳感器,太陽能電池等方面有著廣泛的潛在應(yīng)用。本論文圍繞中紅外寬帶等離子體吸收器的研究與設(shè)計(jì),主要工作總結(jié)如下:(1)提出并設(shè)計(jì)了一種工作在中紅外波段的超緊湊光柵型多頻帶等離子體超材料吸收器。這種吸收器具有異常緊湊的結(jié)構(gòu)特性,能夠利用小尺寸結(jié)構(gòu)單元實(shí)現(xiàn)對較長紅外波進(jìn)行吸收。此外,當(dāng)相鄰單元間距減小時(shí),由于各相鄰單元間的相互耦合,整體吸收譜會(huì)產(chǎn)生紅移現(xiàn)象,進(jìn)一步使得結(jié)構(gòu)小型化成為可能。這種吸收器也是目前為止同類中紅外超材料吸收器中最為緊湊的一種結(jié)構(gòu)。本論文同時(shí)采用了等效LC模型系統(tǒng)地分析并解釋其物理機(jī)制。作為例子,提出并設(shè)計(jì)了一個(gè)單元周期為Λ=3.34μm的四波段吸收器,吸收譜中四個(gè)吸收峰的波長依次為6.9μm,7.9μm,8.9μm和9.97μm,吸收效率分別為99.9%,99.2%,96.1%和87.4%。(2)提出并設(shè)計(jì)了一種多腔陣列型的寬帶中紅外等離子體超材料吸收器,具有高效擴(kuò)展吸收帶寬的同時(shí)保持了吸收器結(jié)構(gòu)緊湊厚度薄的特點(diǎn)。提出了一種“之”字形的設(shè)計(jì)方法避免相鄰諧振腔之間的耦合導(dǎo)致的帶寬減小。同時(shí)分別設(shè)計(jì)了兩層和三層結(jié)構(gòu)的吸收器,中心帶寬8.1μm,半峰全寬分別為25%和48%,并且吸收特性不依賴于角度變化。這種結(jié)構(gòu)同時(shí)能夠擴(kuò)展到其他如太赫茲以及微波波段。(3)提出了一種工作在紅外波段的基于石墨烯負(fù)載的具有十字裂縫結(jié)構(gòu)的用于寬頻光調(diào)制的超材料可調(diào)吸收器。石墨烯-光耦合作用由于裂縫結(jié)構(gòu)中產(chǎn)生的耦合磁共振顯著增強(qiáng),從而克服石墨烯在中紅外的泡利阻塞效應(yīng),實(shí)現(xiàn)了吸收峰大范圍調(diào)制的調(diào)制器。數(shù)值仿真表明,在費(fèi)米能級為0.6eV的情況下,兩個(gè)諧峰的調(diào)制范圍均在其原始諧振波長的20.1%和25.5%,遠(yuǎn)大于之前的一些工作。同時(shí)采用了石墨烯等效電感模型分析了石墨烯調(diào)制的物理機(jī)制以及與調(diào)制寬度超材料幾何結(jié)構(gòu)之間的關(guān)系。這種器件在生物探測,光通信以及成像等領(lǐng)域有著極為廣泛的應(yīng)用。
[Abstract]:Plasma supermaterial is a kind of artificial electromagnetic material with metal-dielectric micro-nano structure, which has special electromagnetic properties which are difficult to obtain from natural materials. In the last ten years, plasma metamaterials have attracted wide interest and carried out a lot of research in the field of scientific research. In many applications of plasma supermaterial, one of the most important fields is supermaterial electromagnetic absorber. The early absorbers depend on the absorption characteristics of the material itself, which inevitably lead to the disadvantages of large volume and low absorption efficiency. The plasma supermaterial is based on metal nanostructure excited plasmon resonance to perfectly absorb the incident light with 100% absorptivity. This kind of absorber has a series of advantages, such as deep subwavelength scale, perfect absorption and adjustable resonant frequency, etc. It has a wide range of potential applications in such fields as thermal radiation emitter, sensor, solar cell and so on. This thesis focuses on the research and design of the mid-infrared broadband plasma absorber. The main work is summarized as follows: 1) A super-compact grating type multi-band plasma superabsorber working in the mid-infrared band is proposed and designed. This kind of absorber has very compact structure and can absorb long infrared wave by using small size structure element. In addition, when the distance between adjacent elements is reduced, the whole absorption spectrum will be red-shifted due to the coupling between adjacent elements, which makes it possible for the structure to be miniaturized. This kind of absorber is also the most compact structure in the same kind of mid-infrared supermaterial absorber so far. At the same time, the physical mechanism is analyzed and explained systematically by using the equivalent LC model. As an example, a four-band absorber with a unit period of 3. 34 渭 m is proposed and designed. The wavelengths of the four absorption peaks in the absorption spectrum are 6.9 渭 m, 7.9 渭 m, 8.9 渭 m and 9.97 渭 m, respectively. The absorption efficiency is 99.9% and 99.2% and 87.4%, respectively. A multi-cavity array broadband mid-infrared plasma supermaterial absorber is proposed and designed. It has the characteristic of expanding the absorption bandwidth efficiently and keeping the structure of absorber compact and thin. A "zigzag" design method is proposed to avoid bandwidth reduction caused by coupling between adjacent resonators. At the same time, two-layer and three-layer absorbers are designed. The center bandwidth is 8.1 渭 m, the full half-width is 25% and 48% respectively, and the absorption characteristics are independent of the angle variation. This structure can also be extended to other structures such as terahertz and microwave-band. A kind of metamaterial tunable absorber with graphene supported graphene based on infrared band for wide-band optical modulation is proposed. The coupling magnetic resonance (Mr) produced by the crack structure is significantly enhanced in graphene optical coupling cooperation, which overcomes the Pauli blocking effect of graphene in the mid-infrared region and realizes a modulator with a large range of absorption peaks. Numerical simulation shows that when Fermi level is 0.6eV, the modulation ranges of the two harmonic peaks are both 20.1% and 25.5% of the original resonant wavelength, which is much larger than some previous work. At the same time, the physical mechanism of graphene modulation and the relationship between the modulation width and the geometric structure of the supermaterial are analyzed by using the graphene equivalent inductance model. This device has been widely used in biological detection, optical communication and imaging.
【學(xué)位授予單位】：深圳大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB34;O441.6
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本文編號：1900409