Fano resonance and resonant localization of excitonic wave in onedimensional quantum dot array with a ring

Suc-Kyoung Hong,Jae Seok Yoon,Seog Woo Nam,Hyung Jin Yang 한국물리학회 2016 Current Applied Physics Vol.16 No.3

The Fano interference of excitonic wave transmitting through a quantum dot chain array with a ring and the Anderson-like localization of the excitonic wave in the ring side are studied. In the quantum dot chain array with a ring, propagating excitonic waves via resonant dipoleedipole interaction interfere with the scattered excitonic wave from the ring and results in the Fano resonance. The excitation energy through the ring is transmitted, reflected, or localized depending on the dipoleedipole couplings to the Fano defect in the ring and transition energy detuning of the defect. Consequently, under some particular conditions, the excitation is resonantly localized in the ring side in the sense of Anderson-like localization by the destructive interference of the totally reflected wave from the ring with the incoming excitonic wave.

Demonstration of Magnetic Confinement in Graphene with Fano-type Resonances

명노준,서경철,임국형 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.2

We demonstrate the magnetic confinement in graphene by investigating the Fano-type resonant features in the transmission spectra. The Fano-type resonance occurs due to the interference between extended states and magnetically-bound states as a result of the interaction of Dirac fermions with the oscillating field. We also find another type of resonance that results from the quasi-bound states induced by the oscillating field. In contrast to the magnetically-bound states, the quasibound states generally have complex eigenenergies whose imaginary parts are associated with finite lifetimes. The results may inspire experimental research on magnetic confinement in graphene.

Ultrasmooth, Highly Spherical Monocrystalline Gold Particles for Precision Plasmonics

Lee, You-Jin,Schade, Nicholas B.,Sun, Li,Fan, Jonathan A.,Bae, Doo Ri,Mariscal, Marcelo M.,Lee, Gaehang,Capasso, Federico,Sacanna, Stefano,Manoharan, Vinothan N.,Yi, Gi-Ra American Chemical Society 2013 ACS NANO Vol.7 No.12

<P>Ultrasmooth, highly spherical monocrystalline gold particles were prepared by a cyclic process of slow growth followed by slow chemical etching, which selectively removes edges and vertices. The etching process effectively makes the surface tension isotropic, so that spheres are favored under quasi-static conditions. It is scalable up to particle sizes of 200 nm or more. The resulting spherical crystals display uniform scattering spectra and consistent optical coupling at small separations, even showing Fano-like resonances in small clusters. The high monodispersity of the particles we demonstrate should facilitate the self-assembly of nanoparticle clusters with uniform optical resonances, which could in turn be used to fabricate optical metafluids. Narrow size distributions are required to control not only the spectral features but also the morphology and yield of clusters in certain assembly schemes.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-12/nn404765w/production/images/medium/nn-2013-04765w_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn404765w'>ACS Electronic Supporting Info</A></P>

테라헤르츠 비대칭 분리고리공진기 메타물질의 높은 품질인자를 위한 공진 특성에 관한 연구

박대준(Dae-Jun Park),류한철(Han-Cheol Ryu) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.11

본 논문에서는 높은 감도의 테라헤르츠 센서로 응용이 가능한 고품질 비대칭 분리고리공진기(ASLR: Asymmetric Split-Loop Resonator) 메타물질의 구조적인 비대칭 정도에 따른 ASLR의 공진특성 변화를 전자기 시뮬레이션을 통하여 분석하였다. 특히, ASLR의 구조적 비대칭성은 높은 품질인자를 갖는 파노공진을 발생시키므로 ASLR의 비대칭성 정도에 따라서 ASLR 고유공진과 파노공진의 공진주파수 변화와 투과계수 및 품질인자의 변화를 분석하였다. 또한, ASLR의 구조적 비대칭성에 따른 ASLR의 공진 특성 변화의 원인을 분석하기 위해 표면전류밀도를 계산하여 ASLR 공진의 공진주파수, 투과계수, 그리고 품질인자가 변화하는 이유를 분석하였다. 이를 통하여 ASLR 고유공진의 표면전류밀도는 이중 극자를 형성하여 높은 방사 손실을 가지게 되므로 품질인자가 낮아지게 되고, 파노공진의 표면전류밀도는 닫힌 모드 또는 사중 극자를 형성하여 이중 극자에 비하여 낮은 방사 손실을 가지므로 파노공진 상태의 ASLR이 높은 품질인자를 가지게 됨을 확인하였다. 이러한 ASLR의 파노공진 특성 분석 결과를 바탕으로 메타물질의 비대칭성을 조절하면 높은 품질인자를 가지는 테라헤르츠 고성능 필터 또는 고감도 센서 개발이 가능하다. 이러한 고감도 고성능 테라헤르츠 소자 개발은 테라헤르츠 메타물질의 실질적인 산업 응용을 유도할 것으로 기대한다. A terahertz asymmetric split-loop resonator (ASLR) was analyzed for use in high-sensitivity sensing applications. Its structural asymmetricity induces an asymmetric Fano resonance which has a high quality factor compared to the symmetric eigen-resonance. The variations of the resonant frequency, transmission coefficient, and quality factor of the ASLR in the eigen and Fano resonances are analyzed as a function of its structural asymmetricity. Also, the surface current densities on the ASLR in both resonances are calculated to analyze the main cause of the variations of its transmission characteristics. The surface current of the ASLR in the eigen resonance shows a dipole resonance, which increases the radiation loss and reduces the quality factor. On the other hand, the surface current of the ASLR in the Fano resonance shows a trapped or quadrupole mode which has a low radiation loss. Therefore, the ASLR operated in the Fano resonance has a high quality factor. Terahertz, high-performance filters and high sensitivity sensors can be developed based on our analysis results of the ASLR having a high quality factor. These high-performance devices based on terahertz metamaterials could increase the adoption of terahertz industrial applications.

Fano resonance in electronic transport induced by the magnetic confinement in a graphene nanoribbon

명노준,임국형,Kyungchul Seo 한국물리학회 2013 Current Applied Physics Vol.13 No.7

Based on the Floquet scattering theory, a model of graphene-based electronic device is presented, in which electrical transport is controlled by adjusting Dirac fermions energy near resonance conditions. The presence of an oscillating field leads to the Fano resonance in transport through a magnetic structure in an armchair graphene nanoribbon (AGNR). The Fano resonance originates from bound states of the magnetic confinement, according to subband indices in the AGNR. The ballistic conductance is markedly affected by the Fano resonance due to the quasi-one-dimensional nature of AGNRs. The results may help realizing graphene electronics with the resonant characteristics in the conductance.

Universal behaviour of high-Q Fano resonances in metamaterials: terahertz to near-infrared regime

Lim Wen Xiang,Singh Ranjan 나노기술연구협의회 2018 Nano Convergence Vol.5 No.5

The observation of Fano resonance phenomena is universal across several branches of physics. Photonics is one of the most important areas of physics that mainly deals with the control of light propagation and localization through its interaction with natural and artificially engineered media. In an era of miniaturization, manipulation of light at micro-nanoscales has assumed unprecedented significance due to its potential to satisfy the mankind with disruptive future technologies. In this work, we present our study on the universality of high quality factor Fano resonances in planar metamaterials across terahertz and infrared parts of the electromagnetic spectrum. The narrow linewidth asymmetric Fano resonant metamaterials have tremendous potential to find applications in micro-nanoscale flat lasers, sensors, and ultra-resolution spectrometers.

Optical method for detecting the concentration of sucrose based on plasmonic nanostructures

Zhu Jun,Yin Jinguo 한국탄소학회 2022 Carbon Letters Vol.32 No.2

We report the first observation of Fano resonance in the Y-shaped cavity (YC), demonstrate that the sensitivity of the sensor is as high as 1160 nm/RIU, much higher than that of the aforementioned sensors, and observe that the quality factor and sensitivity of Fano resonance can be adjusted by changing the geometry of the sensor or adding silver nanoparticles. Traditional sucrose detection methods either waste resources or pollute the environment. This work shows that the sensor can be used to detect the concentration of sucrose. In addition, we found that the concentration of sucrose has a linear relationship with its corresponding refractive index. The sensor we designed can easily and rapidly calculate the concentration of a sucrose solution based on the Fano resonance wavelength shift, which is an important first step towards detecting the refractive index of the solution and identify the composition.

Fano resonance in electronic transport induced by the magnetic confinement in a graphene nanoribbon

Myoung, N.,Ihm, G.,Seo, K. Elsevier 2013 Current Applied Physics Vol.13 No.7

Based on the Floquet scattering theory, a model of graphene-based electronic device is presented, in which electrical transport is controlled by adjusting Dirac fermions energy near resonance conditions. The presence of an oscillating field leads to the Fano resonance in transport through a magnetic structure in an armchair graphene nanoribbon (AGNR). The Fano resonance originates from bound states of the magnetic confinement, according to subband indices in the AGNR. The ballistic conductance is markedly affected by the Fano resonance due to the quasi-one-dimensional nature of AGNRs. The results may help realizing graphene electronics with the resonant characteristics in the conductance.

Variation of Dynamic Fano Resonances in Semiconductor Superlattices Driven by Dc and THz Fields

제구철 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.3

We describe the dynamic Fano resonances in a biased three-dimensional semiconductor superlattice driven by combined dc and THz fields. The Fano resonances on the Wannier Stark ladders are dominantly changed by the THz field via the band collapse phenomenon. The Fano coupling matrix is closely related to the separated energy distance between the two types of exciton resonances produced by the dc and the THz fields. The dynamic Fano coupling strength increases as the exciton resonance induced by the THz field approaches the Wannier exciton states.

Multichannel Quantum Defect Theory Analysis of Overlapping Resonance Structures in Lu-Fano Plots of Rare Gas Spectra

이천우,Ja-Hyun Kong 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.8

Although overlapping resonances have been studied extensively in conventional resonance theories, there have not been many studies on them in multichannel quantum defect theories (MQDT). In MQDT, overlapping resonances occur between the channels instead of states, which pose far greater difficulty. Their systematic treatment was obtained for cases involving degenerate closed channels by applying our previous theory, which decouples background scattering from the resonance scattering in the MQDT formulation. The use of mathematical theory on con-diagonalization and con-similarity was essential for handling the non-Hermitian symmetric complex matrix. Overlapping resonances in rare gas spectra of Ar, Kr and Xe were analyzed using this theory and the results were compared with the ones of the previous alternative parameterizations of MQDT which make the open-open part Koo and closed-closed part Kcc of reactance submatrices zero. The comparison revealed that separation of background and resonance scatterings achieved in our formulation in a systematic way was not achieved in the representation of Koo = 0 and Kcc = 0 when overlapping resonances are present.