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1.
In this work, we demonstrate surface plasmon resonance properties and field confinement under a strong interaction between a waveguide and graphene nanoribbons (GNRs), obtained by coupling with a nanocavity. The optical transmission of a waveguide–cavity–graphene structure is investigated by finite-difference time-domain simulations and coupled-mode theory. The resonant frequency and intensity of the GNR resonant modes can be precisely controlled by tuning the Fermi energy and carrier mobility of the graphene, respectively. Moreover, the refractive index of the cavity core, the susceptibility χ(3) and the intensity of incident light have little effect on the GNR resonant modes, but have good tunability to the cavity resonant mode. The cavity length also has good tunability to the resonant mode of cavity. A strong interaction between the GNR resonant modes and the cavity resonant mode appears at a cavity length of L1 = 350 nm. We also demonstrate the slow-light effect of this waveguide–cavity–graphene structure and an optical bistability effect in the plasmonic cavity mode by changing the intensity of the incident light. This waveguide–cavity–graphene structure can potentially be utilised to enhance optical confinement in graphene nano-integrated circuits for optical processing applications. 相似文献
2.
P. J. Castro J. J. Barroso R. A. Correa M. C. A. Nono 《International Journal of Infrared and Millimeter Waves》1992,13(1):91-104
Experiments have been conducted to characterize a gyrotron cavity designed to operate in theTE
021 mode at 10 GHz. Cavity excitation was accomplished via a coupling hole introduced into the cavity wall and mode detection was carried out by means of two experimental arrangements. In the first, electromagnetic energy is coupled into a receiving waveguide through a small second hole drilled in the opposite side of the cavity. The other scheme uses a horn antenna to receive the power reradiated by the open resonator. Both schemes are discussed regarding mode detection, and measured data includes resonant frequency, loadedQ factor, axial electric field profile and farfield radiation pattern. Evaluation of the loadedQ factor is based on bandwidth measurements whereas standing-wave electric field profile is determined by using perturbation techniques. For severalTE modes, close agreeent between theory and experiment is found. 相似文献
3.
Young Hun Yu Sang Chill Lee Doo Chul Kim Chao Zhang P. Harrison 《Optics & Laser Technology》2004,36(7):535-580
The resonant wavelength and mode radius of the fundamental modes supported by an oxide apertured terahertz vertical surface emitting laser are determined from Gaussian resonant theory and scalar variational method. The reflectivity of the Bragg mirror is calculated for the lowest modes and it decreases as the aperture size decreases. The aperture radius, thickness, and axial position in the cavity are shown to be an important factor for high efficiency vertical cavity surface emitting lasers and single mode operation. When the aperture size is much larger than the emitting wavelength, the optical loss is negligible. However, the optical loss strongly depends on the aperture size and thickness when aperture size is similar to or smaller than emitting wavelength. 相似文献
4.
由光子晶体局域模对称关系分析其简并性 总被引:6,自引:6,他引:0
使用平面波展开法计算了二维正方格子介质柱光子晶体在改变中央介质柱半径的情况下谐振腔的模式,根据所计算的局域模式场分布的对称关系,研究了二维光子晶体谐振腔模式的简并性.结果表明:具有C4v对称群光子晶体谐振腔,存在着二重简并偶极模和二重简并六极模,同时也存在非简并单极模和四极模,二重简并模的90°旋转态与其形成简并对.模式的简并与非简并可以直观地通过考察模式场分布的对称关系而得到. 相似文献
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6.
We measured the decay rates of two degenerate surface plasmon modes in Au nanohole arrays with different hole sizes by angle-resolved reflectivity spectroscopy. For each hole size, at the spectral region where resonant coupling occurs, we observed a large modification in decay rates, leading to the formation of dark and bright modes. The change in decay rates is well explained by temporal coupled mode theory. The deduced coupling constant is found to increase with increasing hole diameter. This study provides us a simple and effective means to control the decay rates of dark and bright modes, which are useful in plasmonic applications. 相似文献
7.
采用传输矩阵方法利用半经典的线性色散模型,计算半导体微腔内同时存在重空穴激子、轻空穴激子时,在不同入射角度下的反射谱,同时,利用三简谐振子耦合模型计算了在不同入射角度下,腔模同时和重空穴激子模、轻空穴激子模耦合所形成的三支腔极化激元的能量,以及腔模、重空穴激子模、轻空穴激子模分别在三支腔极化激元中所占的权重,结果表明随着入射角的增加腔极化激元的高能支和两个低能支之间存在明显的反交叉现象,同时,腔模和重空穴激子模、轻空穴激子模在腔极化激元中所占的权重呈现增加或减小的趋势
关键词:
半导体微腔
腔极化激元
激子 相似文献
8.
G. Krenz S. Bux S. Slama C. Zimmermann P.W. Courteille 《Applied physics. B, Lasers and optics》2007,87(4):643-647
Imperfections in the surface of intracavity elements of an optical ring resonator can scatter light from one mode into the
counterpropagating mode. The phase-locking of the cavity modes induced by this backscattering is a well-known example that
notoriously afflicts laser gyroscopes and similar active systems. We experimentally show how backscattering can be circumvented
in a unidirectionally operated ring cavity either by an appropriate choice of the resonant cavity mode or by active feedback
control.
PACS 42.60.Da; 45.40.Cc; 42.79.Bh; 42.55.-f 相似文献
9.
研究了一种空气槽光子晶体微腔,这种腔是由在平板型光子晶体上引入一条宽度可以调节的线缺陷空气槽形成的.腔模的电场被强烈局限在空气槽中,由于介电常量的不连续性,电场得到很大的提高,同时模体积被大大地降低.数值模拟与分析了微腔的能带结构和场分布,考虑到腔模的谐振频率和对称性,发现一阶偶膜同时具有较高的品质因子和较小的模体积;应用有限时域差分法,得到腔模的品质因子可以高达106,模体积仅为0.02(λ/n)3.计算了一阶偶模谐振波长随空气槽宽度以及空气孔半径的变化,发现随着宽度的增加,波长越来越短.而随着空气孔半径的增加,波长近似线性地减小;当空气孔半径为170 nm时,可以获得最高的腔品质因子. 相似文献
10.
Numerical Simulation and Analysis of a New Type of Complex Cavity for Gyrotron Applications 总被引:1,自引:0,他引:1
Jirun Luo Wei Guo Min Zhu 《International Journal of Infrared and Millimeter Waves》2005,26(12):1703-1711
A new type of complex cavity structure is used to improve the selectivity of modes in gyrotron resonant cavity with a rational
position of inter-cavity wall and the shape of coupling holes between inter- and outer-cavities. The resonant characteristics
of the complex cavity operating in TE021/TE031 mode at Ka frequency band are simulated and analyzed with Ansoft HFSS code, which shows that mode competition can effectively
be alleviated with the cavity structure and it may be useful to the formation of clustered-cavity for extending interaction
frequency bandwidth. 相似文献
11.
研究了以InAs量子点为有源区的二维GaAs基光子晶体微腔的设计与制作,测试并分析了室温下微腔的光谱特性.观察到了波长约为1137 nm,谱线半高宽度约为1 nm的尖锐低阶谐振模式发光峰.我们比较了不同刻蚀条件下光子晶体微腔的发光谱线,结果表明空气孔洞截面的垂直度是影响光子晶体微腔发光特性的重要因素之一.通过调节干法刻蚀工艺,改变空气孔半径与晶格常数的比率,可以在较大范围内调节谐振模式发光峰位置,达到谐振模式与量子点发光峰调谐的目的. 相似文献
12.
研究了光子晶体加载矩形谐振腔,针对传统光子晶体加载无法完全抑制模式竞争的问题,提出了特性阻抗和介质加载方法进行改进,完全实现了谐振腔的高次模式的单模工作,为抑制高次模式工作的谐振腔中模式竞争的问题提供了一种新方法.在此基础之上,采用解析方法以及高频仿真软件HFSS,设计了一个采用TM530高次模式工作的传统光子晶体加载的谐振腔,进一步采用了该新方法对其进行改进,并深入分析了采用这种方法抑制模式竞争的物理原因.计算结果表明,新方法能有效抑制模式竞争,实现谐振腔的高次工作模式的单模工作.
关键词:
光子晶体
谐振腔
模式竞争
特性阻抗 相似文献
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14.
Superenhanced light transmission through subwavelength rectangular hole
arrays have been reported and some investigations have been made into the
physical origin of this phenomenon [K.J. Klein Koerkamp et al., Phys. Rev. Lett.
92, 183901 (2004)]. In our current work, by performing FDTD (finite
difference in the time domain) numerical simulations, we demonstrate that
mechanism that is different from surface plasmon polaritons set up by the
periodicity at the in-plane metal surfaces may account for this
superenhanced light transmission. We suggest that for arrays of rectangular
holes with small enough width in comparison to the wavelength of the
incident light, standing electromagnetic fields can be set up inside the
cavity by the surface plasmons on the hole walls with its intensity being
substantially enhanced inside the cavity. So resonant cavity-enhanced light
transmission is predominant and responsible for its superenhanced light
transmission. Rectangular holes behave as Fabry-Pérot resonance cavities
except that the frequency of their fundamental modes is restricted by their
TM cutoff frequency. However we believe that both localized surface plasmon
modes and surface plasmon polaritons set up by the periodicity at the
in-plane metal surfaces have their shares in extraordinary optical
transmission of rectangular hole arrays especially when the width of the
rectangular hole is not small enough and the metal film is not thick enough. 相似文献
15.
研究了一种空气槽光子晶体微腔,这种腔是由在平板型光子晶体上引入一条宽度可以调节的线缺陷空气槽形成的,腔模的电场被强烈局限在空气槽中,由于介电常量的不连续性,电场得到很大的提高,同时模体积被大大地降低.数值模拟与分析了微腔的能带结构和场分布,考虑到腔模的谐振频率和对称性,发现一阶偶膜同时具有较高的品质因子和较小的模体积;应用有限时域差分法,得到腔模的品质因子可以高达106,模体积仅为0.02(λ/n)3.计算了一阶偶模谐振波长随空气槽宽度以及空气孔半径的变化,发现随着宽度的增加,波长越来越短.而随着空气孔半径的增加,波长近似线性地减小;当空气孔半径为170 nm时,可以获得最高的腔品质因子. 相似文献
16.
利用准分子激光等离子体技术,在紫外预电离XeCl准分子激光器上获得了最短1.58 ns的短脉冲激光输出。实验中分析了聚焦到薄膜表面的光束能量密度对所产生的等离子体密度的影响,并对不同等离子体密度及维持时间情况下脉冲压缩效果进行了讨论,给出了激光器谐振腔在稳定腔及非稳腔两种工作方式下的实验结果。激光器在稳定腔工作时,脉宽可压缩至2.87 ns;采用非稳腔结构时,在脉冲能量不变情况下减小聚焦光斑面积,提高入射到薄膜表面的能量密度,得到了最短1.58 ns的短脉冲激光输出。该技术适用于任何其它准分子器件。 相似文献
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18.
在谐振腔设计过程中, 谐振腔的品质因数以及谐振频率都是需要考虑的关键因素. 传统的方法是通过减小谐振腔的尺寸或者利用高次模来提高谐振腔的谐振频率, 但是由于两种方法都有其局限性, 导致设计结果并不理想. 通过理论计算与模拟仿真相结合的方法, 对影响谐振腔谐振频率的因素进行分析, 得出了填充介质的材料属性与谐振腔谐振频率的关系. 理论计算显示: 当用“左手介质”作为谐振腔的填充物质时, 可以在不改变谐振腔尺寸的基础上提高谐振频率. 高频结构仿真器(high frequency structure simulator)的仿真数据也证明了以上结果, 从而得出谐振腔的谐振频率可以不受谐振腔尺寸的限制. 相较于传统理论而言, 研究结论有进一步的发展, 为探索和设计新颖的谐振腔提供了理论依据. 相似文献
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20.
Wenyuan Rao 《Optik》2010,121(21):1934-1936
We present a design of all-optical switches based on one-dimensional photonic crystals (1D PhC) doped with nonlinear optical materials. The 1D PhC switch structure is composed of a PhC cavity sandwiched by two accessional PhC microcavities. The center PhC cavity has two resonant frequencies with nearly the same quality factors (Q), while the accessional PhC cavities have the same resonant frequency, which is equal to one of the resonant frequencies of the center cavity. The two accessional PhC cavities cause reduction of Q value in this resonant frequency and result in different Q values of two modes. We realize all-optical switch effect by selecting pump light wavelength at the low Q mode and probe light wavelength at the other mode. The theoretical simulations by using the finite difference time domain method show that the pump light intensity required to realize optical switch effect in the designed switch is 50 times smaller than that in one-dimensional photonic crystals cavity with only one resonant mode. 相似文献