本文選題：石墨烯 + 布洛赫方程　； 參考：《中國(guó)礦業(yè)大學(xué)》2017年碩士論文

【摘要】：石墨烯獨(dú)特的電子結(jié)構(gòu)使其具有優(yōu)良的超快光學(xué)特性,尤其是在太赫茲波范圍內(nèi)。因此本文對(duì)單層石墨烯的超快太赫茲非線性光學(xué)性質(zhì)進(jìn)行了研究。通過(guò)建立石墨烯的光學(xué)布洛赫方程,研究了連續(xù)的太赫茲光場(chǎng)下單層石墨烯的超快動(dòng)態(tài)光學(xué)性質(zhì),并且引入了石墨烯的理論模型。采用理論解析的方法對(duì)布洛赫方程進(jìn)行討論,獲得了石墨烯中載流子濃度,極化強(qiáng)度以及電流強(qiáng)度隨時(shí)間變化的函數(shù)。研究結(jié)果表明,在太赫茲輻射光場(chǎng)下由于泡利不相容和能量守恒原理,使得石墨烯系統(tǒng)建立動(dòng)態(tài)非平衡載流子并達(dá)到飽和的時(shí)間是20-200fs,載流子的濃度隨著入射光頻率的增大而增大,因此能夠在1ps之內(nèi)迅速產(chǎn)生光電流。石墨烯線性光學(xué)響應(yīng)區(qū)是(?)evFE0thω;否則是石墨烯系統(tǒng)非線性光學(xué)響應(yīng)區(qū),E0和ω分別對(duì)應(yīng)入射光的強(qiáng)度和頻率,t為時(shí)間,vF是石墨烯狄拉克點(diǎn)附近電子的費(fèi)米速度。同時(shí)研究發(fā)現(xiàn)光子能量hω越大,電極化強(qiáng)度以及光電流越強(qiáng)。我們的理論研究結(jié)果與已有的眾多實(shí)驗(yàn)結(jié)果一致,這表明石墨烯在超快動(dòng)態(tài)光學(xué)領(lǐng)域擁有重要的研究和應(yīng)用價(jià)值。基于石墨烯的光學(xué)布洛赫方程理論,對(duì)單層石墨烯在太赫茲高斯脈沖光場(chǎng)下的光學(xué)特性也進(jìn)行了研究。研究結(jié)果表明石墨烯在太赫茲波段具有非常顯著的非線性超快光學(xué)特性,這是因?yàn)槭┦橇銕兜依讼到y(tǒng),且在狄拉克點(diǎn)附近能量是線性分布的。同時(shí)研究發(fā)現(xiàn)石墨烯載流子濃度,極化強(qiáng)度以及電流強(qiáng)度隨著太赫茲脈沖頻率的增加而增加,這表明石墨烯在超快動(dòng)態(tài)太赫茲領(lǐng)域擁有重要的研究和應(yīng)用價(jià)值。
[Abstract]:Graphene has excellent ultrafast optical properties due to its unique electronic structure, especially in the terahertz wave range. Therefore, the ultrafast terahertz nonlinear optical properties of graphene monolayer are studied. By establishing the optical Bloch equation of graphene, the ultrafast dynamic optical properties of monolayer graphene under continuous terahertz light field are studied, and the theoretical model of graphene is introduced. The Bloch equation is discussed by theoretical analysis, and the functions of carrier concentration, polarization intensity and current intensity with time in graphene are obtained. The results show that under terahertz radiation field, because of Pauli incompatibility and energy conservation principle, It is found that the dynamic non-equilibrium carriers in graphene system can be set up and saturated for 20-200 fs. the carrier concentration increases with the increase of incident light frequency, so the photocurrent can be generated rapidly in 1ps. The linear optical response region of graphene is FE0th 蠅; otherwise, the nonlinear optical response region E0 and 蠅 of graphene system correspond to the intensity and frequency of incident light respectively. The time = v F is the Fermi velocity of electrons near the graphene Dirac point. It is also found that the greater the photon energy h 蠅, the stronger the polarization intensity and photocurrent. Our theoretical results are consistent with many experimental results, which indicates that graphene has important research and application value in ultrafast dynamic optics. Based on the theory of optical Bloch equation of graphene, the optical properties of graphene monolayer in terahertz Gao Si pulsed light field are also studied. The results show that graphene has very significant nonlinear ultrafast optical properties in terahertz because graphene is a zero-band gap Dirac system and the energy distribution is linear near Dirac point. At the same time, it is found that the carrier concentration, polarization intensity and current intensity of graphene increase with the increase of terahertz pulse frequency, which indicates that graphene has important research and application value in ultrafast dynamic terahertz field.
【學(xué)位授予單位】：中國(guó)礦業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O613.71

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 董海明;;摻雜石墨烯系統(tǒng)電場(chǎng)調(diào)控的非線性太赫茲光學(xué)特性研究[J];物理學(xué)報(bào);2013年23期

2 鄒志宇;戴博雅;劉忠范;;石墨烯的化學(xué)氣相沉積生長(zhǎng)與過(guò)程工程學(xué)研究[J];中國(guó)科學(xué):化學(xué);2013年01期

相關(guān)博士學(xué)位論文 前1條

1 李海東;石墨烯納米結(jié)構(gòu)中的電子輸運(yùn)性質(zhì)[D];吉林大學(xué);2009年

，

本文編號(hào)：2036692