One-dimensional photonic crystals
Shen, Huaizhong; Wang, Zhanhua; Wu, Yuxin; Yang, Bai
2016-01-01
A one-dimensional photonic crystal (1DPC), which is a periodic nanostructure with a refractive index distribution along one direction, has been widely studied by scientists. In this review, materials and methods for 1DPC fabrication are summarized. Applications are listed, with a special emphasis
One-dimensional photonic quasicrystals
Ghulinyan, Mher
2015-01-01
In this chapter, first we will address principal aspects of 1D quasiperiodicity with a particular focus on 1D Fibonacci chains. Further, the rest of the chapter will be dedicated to the electromagnetic counterpart of 1D Fibonacci structures as a relatively simplest case of the large class of photonic quasicrystals.
Solitons in one-dimensional photonic crystals
Mayteevarunyoo, Thawatchai
2008-01-01
We report results of a systematic analysis of spatial solitons in the model of 1D photonic crystals, built as a periodic lattice of waveguiding channels, of width D, separated by empty channels of width L-D. The system is characterized by its structural "duty cycle", DC = D/L. In the case of the self-defocusing (SDF) intrinsic nonlinearity in the channels, one can predict new effects caused by competition between the linear trapping potential and the effective nonlinear repulsive one. Several species of solitons are found in the first two finite bandgaps of the SDF model, as well as a family of fundamental solitons in the semi-infinite gap of the system with the self-focusing nonlinearity. At moderate values of DC (such as 0.50), both fundamental and higher-order solitons populating the second bandgap of the SDF model suffer destabilization with the increase of the total power. Passing the destabilization point, the solitons assume a flat-top shape, while the shape of unstable solitons gets inverted, with loc...
One-Dimensional Tunable Photonic-Crystal IR Filter Project
National Aeronautics and Space Administration — MetroLaser proposes to design and develop an innovative narrowband tunable IR filter based on the properties of a one-dimensional photonic crystal structure with a...
One-Dimensional Tunable Photonic-Crystal IR Filter Project
National Aeronautics and Space Administration — MetroLaser proposes to design and develop an innovative narrowband tunable IR filter based on the properties of a one-dimensional photonic crystal structure with a...
One Dimensional Polymeric Organic Photonic Crystals for DFB Lasers
Directory of Open Access Journals (Sweden)
F. Scotognella
2008-01-01
Full Text Available We present a very simple method to realize a one-dimensional photonic crystal (1D PC, consisting of a dye-doped polymeric multilayer. Due to the high photonic density of states at the edges of the photonic band-gap (PBG, a surface emitting distributed feedback (DFB laser is obtained with this structure. Furthermore, the incidence angle dependence of the PBG of the polymeric multilayer is reported.
One-dimensional photonic crystals bound by light
Cui, Liyong; Li, Xiao; Chen, Jun; Cao, Yongyin; Du, Guiqiang; Ng, Jack
2017-08-01
Through rigorous simulations, the light scattering induced optical binding of one-dimensional (1D) dielectric photonic crystals is studied. The optical forces corresponding to the pass band, band gap, and band edge are qualitatively different. It is shown that light can induce self-organization of dielectric slabs into stable photonic crystals, with its lower band edge coinciding with the incident light frequency. Incident light at normal and oblique incidence and photonic crystals with parity-time symmetry are also considered.
Negative Refraction Angular Characterization in One-Dimensional Photonic Crystals
Jesus Eduardo Lugo; Rafael Doti; Jocelyn Faubert
2011-01-01
BACKGROUND: Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here we experimentally characterize negative refraction in a one dimensional photonic crystal structure; near the low frequency edge of the fourth photonic bandgap. We compare the experimental results with current theory and a theory based on the group velocity d...
Black Phosphorus based One-dimensional Photonic Crystals and Microcavities
Kriegel, I
2016-01-01
The latest achievements in the fabrication of black phosphorus thin layers, towards the technological breakthrough of a phosphorene atomically thin layer, are paving the way for a their employment in electronics, optics, and optoelectronics. In this work, we have simulated the optical properties of one-dimensional photonic structures, i.e. photonic crystals and microcavities, in which few-layer black phosphorus is one of the components. The insertion of the 5 nm black phosphorous layers leads to a photonic band gap in the photonic crystals and a cavity mode in the microcavity interesting for light manipulation and emission enhancement.
The Quantum Well of One-Dimensional Photonic Crystals
Directory of Open Access Journals (Sweden)
Xiao-Jing Liu
2015-01-01
Full Text Available We have studied the transmissivity of one-dimensional photonic crystals quantum well (QW with quantum theory approach. By calculation, we find that there are photon bound states in the QW structure (BA6(BBABBn(AB6, and the numbers of the bound states are equal to n+1. We have found that there are some new features in the QW, which can be used to design optic amplifier, attenuator, and optic filter of multiple channel.
Topological modes in one-dimensional solids and photonic crystals
Atherton, Timothy J.; Butler, Celia A. M.; Taylor, Melita C.; Hooper, Ian R.; Hibbins, Alastair P.; Sambles, J. Roy; Mathur, Harsh
2016-03-01
It is shown theoretically that a one-dimensional crystal with time-reversal and particle-hole symmetries is characterized by a topological invariant that predicts the existence or otherwise of edge states. This is confirmed experimentally through the construction and simulation of a photonic crystal analog in the microwave regime. It is shown that the edge mode couples to modes external to the photonic crystal via a Fano resonance.
The electromagnetic Brillouin precursor in one-dimensional photonic crystals
Uitham, R.; Hoenders, B. J.
2008-01-01
We have calculated the electromagnetic Brillouin precursor that arises in a one-dimensional photonic crystal that consists of two homogeneous slabs which each have a single electron resonance. This forerunner is compared with the Brillouin precursor that arises in a homogeneous double-electron reson
The electromagnetic Brillouin precursor in one-dimensional photonic crystals
Uitham, R.; Hoenders, B. J.
2008-01-01
We have calculated the electromagnetic Brillouin precursor that arises in a one-dimensional photonic crystal that consists of two homogeneous slabs which each have a single electron resonance. This forerunner is compared with the Brillouin precursor that arises in a homogeneous double-electron
Strongly interacting photons in one-dimensional continuum
Roy, Dibyendu; Firstenberg, Ofer
2016-01-01
The photon-photon scattering in vacuum is extremely weak. However, strong effective interactions between single photons can be realized by employing strong light-matter coupling. These interactions are a fundamental building block for quantum optics, bringing many-body physics to the photonic world and providing important resources for quantum photonic devices and for optical metrology. In this Colloquium, we review the physics of strongly-interacting photons in one-dimensional systems with no optical confinement along the propagation direction. We focus on two recently-demonstrated experimental realizations: (i) superconducting qubits coupled to open transmission lines, and (ii) interacting Rydberg atoms in a cold gas. Advancements in the theoretical understanding of these systems are presented in complementary formalisms and compared to experimental results. The experimental achievements are summarized alongside of a systematic description of the quantum optical effects and quantum devices emerging from the...
One-dimensional photonic band gaps in optical lattices
Samoylova, Marina; Holynski, Michael; Courteille, Philippe Wilhelm; Bachelard, Romain
2013-01-01
The phenomenon of photonic band gaps in one-dimensional optical lattices is reviewed using a microscopic approach. Formally equivalent to the transfer matrix approach in the thermodynamic limit, a microscopic model is required to study finite-size effects, such as deviations from the Bragg condition. Microscopic models describing both scalar and vectorial light are proposed, as well as for two- and three-level atoms. Several analytical results are compared to experimental data, showing a good agreement.
Lateral shift in one-dimensional quasiperiodic chiral photonic crystal
Energy Technology Data Exchange (ETDEWEB)
Da, Jian, E-mail: dajian521@sina.com [Department of Information Engineering, Huaian Senior Vocational and Technical School, Feiyao road, Huaian 223005, Jiangsu Province (China); Mo, Qi, E-mail: moqiyueyang@163.com [School of Software, Yunnan University, Cuihu Bai Road, Kunming City, Yunnan Province 650091 (China); Cheng, Yaokun [Department of Information Engineering, Huaian Senior Vocational and Technical School, Feiyao road, Huaian 223005, Jiangsu Province (China); Liu, Taixiang [Taishan Vocational College of Nursing, Shandong Province 271000 (China)
2015-02-01
We investigate the lateral shift of a one-dimensional quasiperiodic photonic crystal consisting of chiral and conventional dielectric materials. The effect of structural irregularity on lateral shift is evaluated by stationary-phase approach. Our results show that the lateral shift can be modulated by varying the structural irregularity in quasiperiodic structure. Besides, the position of peak in lateral shift spectrum stays sensitive to the chiral factor of chiral materials. In comparison with that of periodic structure, quasiperiodic structure provides an extra degree of freedom to manipulate the lateral shift.
Negative refraction angular characterization in one-dimensional photonic crystals.
Directory of Open Access Journals (Sweden)
Jesus Eduardo Lugo
Full Text Available BACKGROUND: Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here we experimentally characterize negative refraction in a one dimensional photonic crystal structure; near the low frequency edge of the fourth photonic bandgap. We compare the experimental results with current theory and a theory based on the group velocity developed here. We also analytically derived the negative refraction correctness condition that gives the angular region where negative refraction occurs. METHODOLOGY/PRINCIPAL FINDINGS: By using standard photonic techniques we experimentally determined the relationship between incidence and negative refraction angles and found the negative refraction range by applying the correctness condition. In order to compare both theories with experimental results an output refraction correction was utilized. The correction uses Snell's law and an effective refractive index based on two effective dielectric constants. We found good agreement between experiment and both theories in the negative refraction zone. CONCLUSIONS/SIGNIFICANCE: Since both theories and the experimental observations agreed well in the negative refraction region, we can use both negative refraction theories plus the output correction to predict negative refraction angles. This can be very useful from a practical point of view for space filtering applications such as a photonic demultiplexer or for sensing applications.
Negative refraction angular characterization in one-dimensional photonic crystals.
Lugo, Jesus Eduardo; Doti, Rafael; Faubert, Jocelyn
2011-04-06
Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here we experimentally characterize negative refraction in a one dimensional photonic crystal structure; near the low frequency edge of the fourth photonic bandgap. We compare the experimental results with current theory and a theory based on the group velocity developed here. We also analytically derived the negative refraction correctness condition that gives the angular region where negative refraction occurs. By using standard photonic techniques we experimentally determined the relationship between incidence and negative refraction angles and found the negative refraction range by applying the correctness condition. In order to compare both theories with experimental results an output refraction correction was utilized. The correction uses Snell's law and an effective refractive index based on two effective dielectric constants. We found good agreement between experiment and both theories in the negative refraction zone. Since both theories and the experimental observations agreed well in the negative refraction region, we can use both negative refraction theories plus the output correction to predict negative refraction angles. This can be very useful from a practical point of view for space filtering applications such as a photonic demultiplexer or for sensing applications.
Trapped Atoms in One-Dimensional Photonic Crystals
Kimble, H.
2013-05-01
I describe one-dimensional photonic crystals that support a guided mode suitable for atom trapping within a unit cell, as well as a second probe mode with strong atom-photon interactions. A new hybrid trap is analyzed that combines optical and Casimir-Polder forces to form stable traps for neutral atoms in dielectric nanostructures. By suitable design of the band structure, the atomic spontaneous emission rate into the probe mode can exceed the rate into all other modes by more than tenfold. The unprecedented single-atom reflectivity r0 ~= 0 . 9 for the guided probe field could create new scientific opportunities, including quantum many-body physics for 1 D atom chains with photon-mediated interactions and high-precision studies of vacuum forces. Towards these goals, my colleagues and I are pursuing numerical simulation, device fabrication, and cold-atom experiments with nanoscopic structures. Funding is provided by by the IQIM, an NSF PFC with support of the Moore Foundation, by the AFOSR QuMPASS MURI, by the DoD NSSEFF program (HJK), and by NSF Grant PHY0652914 (HJK). DEC acknowledges funding from Fundacio Privada Cellex Barcelona.
Properties of surface modes in one dimensional plasma photonic crystals
Energy Technology Data Exchange (ETDEWEB)
Shukla, S.; Prasad, S., E-mail: prasad.surendra@gmail.com; Singh, V. [Department of Physics, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India)
2015-02-15
Properties of surface modes supported at the interface of air and a semi-infinite one dimensional plasma photonic crystal are analyzed. The surface mode equation is obtained by using transfer matrix method and applying continuity conditions of electric fields and its derivatives at the interface. It is observed that with increase in the width of cap layer, frequencies of surface modes are shifted towards lower frequency side, whereas increase in tangential component of wave-vector increases the mode frequency and total energy carried by the surface modes. With increase in plasma frequency, surface modes are found to shift towards higher frequency side. The group velocity along interface is found to control by cap layer thickness.
Thermal radiation in one-dimensional photonic quasicrystals with graphene
Costa, C. H.; Vasconcelos, M. S.; Fulco, U. L.; Albuquerque, E. L.
2017-10-01
In this work we investigate the thermal power spectra of the electromagnetic radiation through one-dimensional stacks of dielectric layers, with graphene at their interfaces, arranged according to a quasiperiodic structure obeying the Fibonacci (FB), Thue-Morse (TM) and double-period (DP) sequences. The thermal radiation power spectra are determined by means of a theoretical model based on a transfer matrix formalism for both normal and oblique incidence geometries, considering the Kirchhoff's law of thermal radiation. A systematic study of the consequences of the graphene layers in the thermal emittance spectra is presented and discussed. We studied also the radiation spectra considering the case where the chemical potential is changed in order to tune the omnidirectional photonic band gap.
One-dimensional photonic crystal fishbone hybrid nanocavity with nanoposts
Energy Technology Data Exchange (ETDEWEB)
Lu, Tsan-Wen; Lin, Pin-Tso; Lee, Po-Tsung, E-mail: potsung@mail.nctu.edu.tw [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Rm. 413 CPT Building, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan (China)
2014-05-12
We propose and investigate a one-dimensional photonic crystal (PhC) fishbone (FB) hybrid nanocavity lying on silver substrate with a horizontal air slot. With very few PhC periods, the confined transverse-magnetic, TM{sub 10} hybrid mode concentrated within the air slot shows high quality factor over effective mode volume ratio larger than 10{sup 5}λ{sup −3}. Most importantly, this FB hybrid nanocavity allows formation of low-index nanoposts within the air slot without significantly affecting the mode properties. These nanoposts guarantee the structural stabilities under different environmental perturbations. Furthermore, capabilities of our proposed design in serving as optical sensors and tweezers for bio-sized nanoparticles are also investigated.
A Smart Colorful Supercapacitor with One Dimensional Photonic Crystals
Liu, Cihui; Liu, Xing; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin
2015-12-01
To meet the pressing demands for portable and flexible equipment in contemporary society, developing flexible, lightweight, and sustainable supercapacitor systems with large power densities, long cycle life, and ease of strongly required. However, estimating the state-of-charge of existing supercapacitors is difficult, and thus their service life is limited. In this study, we fabricate a flexible color indicative supercapacitor device with mesoporous polyaniline (mPANI)/Poly(N-Isopropyl acrylamide-Graphene Oxide-Acrylic Acid) (P(NiPPAm-GO-AA)) one dimensional photonic crystals (1DPCs) as the electrode material through a low-cost, eco-friendly, and scalable fabrication process. We found that the state-of-charge could be monitored by the structural color oscillation due to the change in the photonic band gap position of the 1DPCs. The flexible 1DPCs supercapacitor is thin at 3 mm and exhibits good specific capacitance of 22.6 F g-1 with retention of 91.1% after 3,000 cycles. This study shows the application of the 1DPCs supercapacitor as a visual ultrathin power source. The technology may find many applications in future wearable electronics.
A Smart Colorful Supercapacitor with One Dimensional Photonic Crystals.
Liu, Cihui; Liu, Xing; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin
2015-12-22
To meet the pressing demands for portable and flexible equipment in contemporary society, developing flexible, lightweight, and sustainable supercapacitor systems with large power densities, long cycle life, and ease of strongly required. However, estimating the state-of-charge of existing supercapacitors is difficult, and thus their service life is limited. In this study, we fabricate a flexible color indicative supercapacitor device with mesoporous polyaniline (mPANI)/Poly(N-Isopropyl acrylamide-Graphene Oxide-Acrylic Acid) (P(NiPPAm-GO-AA)) one dimensional photonic crystals (1DPCs) as the electrode material through a low-cost, eco-friendly, and scalable fabrication process. We found that the state-of-charge could be monitored by the structural color oscillation due to the change in the photonic band gap position of the 1DPCs. The flexible 1DPCs supercapacitor is thin at 3 mm and exhibits good specific capacitance of 22.6 F g(-1) with retention of 91.1% after 3,000 cycles. This study shows the application of the 1DPCs supercapacitor as a visual ultrathin power source. The technology may find many applications in future wearable electronics.
Transmission properties of one-dimensional ternary plasma photonic crystals
Energy Technology Data Exchange (ETDEWEB)
Shiveshwari, Laxmi [Department of Physics, K. B. Womens' s College, Hazaribagh 825 301 (India); Awasthi, S. K. [Department of Physics and Material Science and Engineering, Jaypee Institute of Information Technology, Noida 201 304 (India)
2015-09-15
Omnidirectional photonic band gaps (PBGs) are found in one-dimensional ternary plasma photonic crystals (PPC) composed of single negative metamaterials. The band characteristics and transmission properties are investigated through the transfer matrix method. We show that the proposed structure can trap light in three-dimensional space due to the elimination of Brewster's angle transmission resonance allowing the existence of complete PBG. The results are discussed in terms of incident angle, layer thickness, dielectric constant of the dielectric material, and number of unit cells (N) for TE and TM polarizations. It is seen that PBG characteristics is apparent even in an N ≥ 2 system, which is weakly sensitive to the incident angle and completely insensitive to the polarization. Finite PPC could be used for multichannel transmission filter without introducing any defect in the geometry. We show that the locations of the multichannel transmission peaks are in the allowed band of the infinite structure. The structure can work as a single or multichannel filter by varying the number of unit cells. Binary PPC can also work as a polarization sensitive tunable filter.
Properties of photonic bandgap in one-dimensional multicomponent photonic crystal
Institute of Scientific and Technical Information of China (English)
ZHANG Yi; WANG Qi
2006-01-01
Properties of photonic band gap and light propagation in one-dimensional multicomponent photonic crystal have been studied with the optical transfer matrix method.We mainly analyze the relation of photonic band-gap property with the arrangement of components,the refractive index and the geometrical thickness.In this study,the methods to change the width and the location of the existing photonic band-gaps in multicomponent photonic crystal are proposed.
Gorelik, V. S.; Voinov, Yu. P.; Shchavlev, V. V.; Bi, Dongxue; Shang, Guo Liang; Fei, Guang Tao
2016-12-01
Mesoporous one-dimensional photonic crystals based on aluminum oxide have been synthesized by electrochemical etching method. Reflection spectra of the obtained mesoporous samples in a wide spectral range that covers several band gaps are presented. Microscopic parameters of photonic crystals are calculated and corresponding reflection spectra for the first six band gaps are presented.
Optical properties of one-dimensional disordered multilayer photonic structures
Scotognella, Francesco; Chiasera, Alessandro; Criante, Luigino; Varas, Stefano; Kriegel, Ilka; Bellingeri, Michele; Righini, Giancarlo C.; Ramponi, Roberta; Ferrari, Maurizio
2014-03-01
The investigation of the differences between ordered and disordered materials (in the hundreds of nanometer lengthscale) is a crucial topic for a better understanding of light transport in photonic media. Here we study the light transmission properties of 1D photonic structures in which disorder is introduced in two different ways. In the first study, we have grouped the high refractive index layers in layer clusters, randomly distributed among layers of low refractive index. We have controlled the maximum size of such clusters and the ratio of the high-low refractive index layers (here called dilution). We studied the total transmission of the disordered structure within the photonic band gap of the ordered structure as a function of the maximum cluster size, and we have observed a valley in trend of the total transmission for a specific maximum cluster size. This value increases with increasing dilution. Furthermore, within one dilution we observe oscillations of the total transmission with increasing cluster size. In the second study, we have realized photonic structures with a random variation of the layer thickness. The structures were fabricated by radio-frequency (RF) sputtering technique. The transmission spectrum of the disordered structure was simulated by taking into account the refractive index dispersion of the materials, resulting in a good agreement between the experimental data and the simulations. We found that the transmission of the photonic structure in the range 300- 1200 nm is lower with respect the corresponding periodic photonic crystal. The studied disordered 1D photonic structures are very interesting for the modelization and realization of broad band filters and light harvesting devices.
One-dimensional photonic bandgap structure in abalone shell
Institute of Scientific and Technical Information of China (English)
LI Bo; ZHOU Ji; LI Longtu; LI Qi; HAN Shuo; HAO Zhibiao
2005-01-01
@@ Photonic bandgap (PBG) materials are periodic com- posites of dielectric materials in which electromagnetic waves of certain frequency range cannot propagate in any or a special direction. Recently, there has been great inter- est in synthetic PBG materials due to their ability in ma- nipulation of photons. Since 500 million years ago, the natural world has been exploiting photonic structures for specific biological purposes[1]. Different types of biologi- cal PBG materials have been discovered in recent years, such as the one-dimension PBG structure in the sea mouse Aphrodita[2], and the fruits Elaeocarpus[3,4]; two-dimension PBG structure in the male peacock Pavo muticus feathers[5], Indonesian male Papilio palinurus butterfly[6], Thaumantis diores butterfly[7] and the male Ancyluris meliboeus Fabricius butterflies[8]; and three-dimension PBG structure in the weevil Pachyrhynchus argus[9].
Photonic gap vanishing in one-dimensional photonic crystals with single-negative metamaterials
Energy Technology Data Exchange (ETDEWEB)
Chen, Yihang, E-mail: kallenmail@sina.com [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); Wang, Yu; Leung, C.W.; Hu, Mingzhe; Chan, H.L.W. [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China)
2011-06-13
The properties of photonic band gap in one-dimensional photonic crystals composed of single-negative metamaterials are studied theoretically. Our study shows that the photonic gap will vanish at a certain incident angle when both the phase-match and impedance-match conditions are satisfied simultaneously, suggesting that the bandwidth and location of the photonic gap are strongly dependent on the incident angle and polarization. However, the photonic gap will not vanish and may become insensitive to the incident angle when the two match conditions cannot be met. Our study also shows that losses in metamaterials have little effect on the properties of the photonic gap. -- Highlights: → Photonic gap of 1D photonic crystal containing metamaterials was investigated. → The gap can be designed to be sensitive or insensitive to the incident angle. → The gap can be designed to be close at a specific incident angle. → Conditions for photonic gap vanishing were proposed. → Losses of metamaterials have little effect on the properties of the photonic gap.
Lyapunov exponents for one-dimensional aperiodic photonic bandgap structures
Kissel, Glen J.
2011-10-01
Existing in the "gray area" between perfectly periodic and purely randomized photonic bandgap structures are the socalled aperoidic structures whose layers are chosen according to some deterministic rule. We consider here a onedimensional photonic bandgap structure, a quarter-wave stack, with the layer thickness of one of the bilayers subject to being either thin or thick according to five deterministic sequence rules and binary random selection. To produce these aperiodic structures we examine the following sequences: Fibonacci, Thue-Morse, Period doubling, Rudin-Shapiro, as well as the triadic Cantor sequence. We model these structures numerically with a long chain (approximately 5,000,000) of transfer matrices, and then use the reliable algorithm of Wolf to calculate the (upper) Lyapunov exponent for the long product of matrices. The Lyapunov exponent is the statistically well-behaved variable used to characterize the Anderson localization effect (exponential confinement) when the layers are randomized, so its calculation allows us to more precisely compare the purely randomized structure with its aperiodic counterparts. It is found that the aperiodic photonic systems show much fine structure in their Lyapunov exponents as a function of frequency, and, in a number of cases, the exponents are quite obviously fractal.
Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.
2010-03-01
We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).
Trapped Atoms in One-Dimensional Photonic Crystals
2013-08-09
2002 J. Opt. Soc. Am. B 19 2052 [39] Koenderink A F, Kafesaki M, Soukoulis C M and Sandoghdar V 2006 J. Opt. Soc. Am. B 23 1196 [40] Manga Rao V S C...032509 [55] Hwang J K, Ryu H Y and Lee Y H 1999 Phys. Rev. B 60 4688–95 [56] Yao P, Manga Rao V S C and Hughes S 2010 Laser Photon. Rev. 4 499–516 New Journal of Physics 15 (2013) 083026 (http://www.njp.org/)
Institute of Scientific and Technical Information of China (English)
Laxmi SHIVESHWARI
2011-01-01
Propagation of electromagnetic waves in one-dimensional plasma dielectric photonic crystals, the superlattice structure consisting of alternating plasma and dielectric materials, is studied theoretically for oblique incidence by using the transfer matrix method. Our results show that complete photonic band gaps for all polarizations can be obtained in one-dimensional plasma dielectric photonic crystals. These structures can exhibit a new type of band or gap, for the incidence other than the normal one, near frequencies where the electric permittivity of the plasma layer changes sign. This new band or gap arises, from the dispersive properties of the plasma layer, only for transverse magnetic polarized waves, and its width increases with the increase in incident angle. This differential behavior under polarization can be utilized in the design of an efficient polarization splitter. The existence of both photonic gaps and resonance transmission bands is demonstrated for experimentally realizable structures such as double electromagnetic barriers.
Neutron and photon (light) scattering on solitons in the quasi-one-dimensional magnetics
Abdulloev, K O
1999-01-01
The general expression we have found earlier for the dynamics form-factor is used to analyse experiments on the neutron and photon (light) scattering by the gas of solitons in quasi-one-dimensional magnetics (Authors)
Broadening of Omnidirectional Photonic Band Gap in Graphene Based one Dimensional Photonic Crystals
Directory of Open Access Journals (Sweden)
Neetika Arora
2015-09-01
Full Text Available A simple design of one dimensional gradual stacked photonic crystal has been proposed. This structure exhibits a periodic array of alternate layers of Graphene and Silica. These are the materials of low and high refractive indices respectively. Here the structure considered has three stacks .Each stack has five alternate layers of Graphene and silica. The transfer matrix method has been used for numerical computation. In this paper, such a structure has wider reflection bands in comparison to a conventional dielectric PC structure and structure with Sio2 and Si layers for a constant gradual constant ϒ at different incident angle.
Optical Properties of One-dimensional Three-component Photonic Band Gap Structure
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
Theoretical study of the optical properties of one-dimensional three-component photonic band gap structure, which is composed of three alternating dielectric layers of different refractive indices and thickness in a unit cell, is performed. This one-dimensional photonic band gap structure exhibits the transparency band and forbidden band. We find that there are several mini-bands of the allowed transmission to be created within the photonic band gap region of the structure if a defect designed specially is introduced inside the structure. This characteristic is very important for some practical applications.
Peak, multi-peak and broadband absorption in graphene-based one-dimensional photonic crystal
Miloua, R.; Kebbab, Z.; Chiker, F.; Khadraoui, M.; Sahraoui, K.; Bouzidi, A.; Medles, M.; Mathieu, C.; Benramdane, N.
2014-11-01
We theoretically investigate the possibility of enhancing light absorption in graphene-based one dimensional photonic crystal. We demonstrate that it is possible to achieve total light absorption at technologically important wavelengths using one-dimensional graphene-based photonic crystals. By means of the transfer matrix method, we investigate the effect of refractive indices and layer numbers on the optical response of the structure. We found that it is possible to achieve one peak, multi-peak or broadband, and complete optical absorption. As a result, the proposed photonic structures enable myriad potential applications such as photodetection, shielding and optical sensing.
Zaghdoudi, J.; Kuszelewicz, R.; Kanzari, M.; Rezig, B.
2008-04-01
Slow light offers many opportunities for photonic devices by increasing the effective interaction length of imposed refractive index changes. The slow wave effect in photonic crystals is based on their unique dispersive properties and thus entirely dielectric in nature. In this work we demonstrate an interesting opportunity to decrease drastically the group velocity of light in one-dimensional photonic crystals constructed form materials with large dielectric constant without dispersion). We use numerical analysis to study the photonic properties of periodic (Bragg mirror) and quasiperiodic one dimensional photonic crystals realized to engineer slow light effects. Various geometries of the photonic pattern have been characterized and their photonic band-gap structure analyzed. Indeed, one dimensional quasi periodic photonic multilayer structure based on Fibonacci, Thue-Morse, and Cantor sequences were studied. Quasiperiodic structures have a rich and highly fragmented reflectivity spectrum with many sharp resonant peaks that could be exploited in a microcavity system. A comparison of group velocity through periodic and quasiperiodic photonic crystals was discussed in the context of slow light propagation. The velocity control of pulses in materials is one of the promising applications of photonic crystals. The material systems used for the numerical analysis are TiO II/SiO II and Te/SiO II which have a refractive index contrast of approximately 1.59 and 3.17 respectively. The proposed structures were modelled using the Transfer Matrix Method.
Observation of localized flat-band modes in a one-dimensional photonic rhombic lattice
Mukherjee, Sebabrata
2015-01-01
We experimentally demonstrate the photonic realization of a dispersionless flat-band in a one-dimensional photonic rhombic lattice fabricated by ultrafast laser inscription. In the nearest neighbor tight binding approximation the lattice supports two dispersive and a non-dispersive (flat) band. We experimentally excite a superposition of flat-band eigen modes at the input of the photonic lattice and show the diffractionless propagation of the input modes due to their infinite effective mass.
DEFF Research Database (Denmark)
Chen, Yuntian; Wubs, Martijn; Mørk, Jesper;
2011-01-01
We study the dynamics of single-photon absorption by a single emitter coupled to a one-dimensional waveguide that simultaneously provides channels for spontaneous emission (SE) decay and a channel for the input photon. We have developed a time-dependent theory that allows us to specify any input ...... can be improved by a further 4% by engineering the dispersion. Efficient single-photon absorption by a single emitter has potential applications in quantum communication and quantum computation....
Observation of localized flat-band modes in a quasi-one-dimensional photonic rhombic lattice.
Mukherjee, Sebabrata; Thomson, Robert R
2015-12-01
We experimentally demonstrate the photonic realization of a dispersionless flat band in a quasi-one-dimensional photonic lattice fabricated by ultrafast laser inscription. In the nearest neighbor tight binding approximation, the lattice supports two dispersive and one nondispersive (flat) band. We experimentally excite superpositions of flat-band eigenmodes at the input of the photonic lattice and show the diffractionless propagation of the input states due to their infinite effective mass. In the future, the use of photonic rhombic lattices, together with the successful implementation of a synthetic gauge field, will enable the observation of Aharonov-Bohm photonic caging.
Energy Technology Data Exchange (ETDEWEB)
Chen, Yihang, E-mail: eon.chen@yahoo.com.cn [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); Wang, Xinggang [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); Yong, Zehui; Zhang, Yunjuan [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Chen, Zefeng [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); He, Lianxing; Lee, P.F.; Chan, Helen L.W.; Leung, Chi Wah [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Wang, Yu, E-mail: apywang@inet.polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China)
2012-03-19
Composite right/left-handed transmission lines with lumped element series capacitors and shunt inductors are used to experimentally realize the one-dimensional photonic crystals composed of single-negative metamaterials. The simulated and experimental results show that a special photonic band gap corresponding to zero-effective-phase (zero-φ{sub eff}) may appear in the microwave regime. In contrast to the Bragg gap, by changing the length ratio of the two component materials, the width and depth of the zero-φ{sub eff} gap can be conveniently adjusted while keeping the center frequency constant. Furthermore, the zero-φ{sub eff} gap vanishes when both the phase-matching and impedance-matching conditions are satisfied simultaneously. These transmission line structures provide a good way for realizing microwave devices based on the zero-φ{sub eff} gap. -- Highlights: ► 1D photonic crystals with metamaterials were investigated experimentally. ► Both Bragg gap and zero-φ{sub eff} gap were observed in the microwave regime. ► The width and depth of the zero-φ{sub eff} gap were experimentally adjusted. ► Zero-φ{sub eff} gap was observed to be close when two match conditions were satisfied.
Simultaneous multi-frequency topological edge modes between one-dimensional photonic crystals.
Choi, Ka Hei; Ling, C W; Lee, K F; Tsang, Y H; Fung, Kin Hung
2016-04-01
We show theoretically that, in the limit of weak dispersion, one-dimensional binary centrosymmetric photonic crystals can support topological edge modes in all photonic bandgaps. By analyzing their bulk band topology, these "harmonic" topological edge modes can be designed in a way that they exist at all photonic bandgaps opened at the center of the Brillouin zone, at all gaps opened at the zone boundaries, or both. The results may suggest a new approach to achieve robust multi-frequency coupled modes for applications in nonlinear photonics, such as frequency upconversion.
The Optical Bloch oscillation in chirped one-dimensional superconducting photonic crystal
Zhang, Zhengren; Long, Yang; Zhang, Liwei; Yin, Pengfei; Xue, Chunhua
2017-09-01
We exploit theoretically the propagation properties of electromagnetic waves in nanoscale one-dimensional superconducting photonic crystal. The Wannier Stark ladders can be formed in the photonic crystal by varying the thickness of the dielectric layers linearly across the structure. The dynamics behavior of a Gaussian pulse transmitting through the structure is simulated theoretically. We find that photons undergo Bloch oscillations inside tilted photonic bands and the Bloch oscillations are sensitive to the change of temperature in the range of 3-8 K. It is demonstrated that our structure is possible to realize tunable optical Bloch oscillations by controlling the temperature of superconducting material.
Modeling of Z-scan characteristics for one-dimensional nonlinear photonic bandgap materials.
Chen, Shuqi; Zang, Weiping; Schülzgen, Axel; Liu, Xin; Tian, Jianguo; Moloney, Jerome V; Peyghambarian, Nasser
2009-12-01
We propose a Z-scan theory for one-dimensional nonlinear photonic bandgap materials. The Z-scan characteristics for this material are analyzed. Results show that the Z-scan curves for photonic bandgap materials with nonlinear refraction are similar to those of uniform materials exhibiting both nonlinear refraction and nonlinear absorption simultaneously. Effects of nonlinear absorption on reflected and transmitted Z-scan results are also discussed.
Frequency bands of negative refraction in finite one-dimensional photonic crystals
Institute of Scientific and Technical Information of China (English)
Chen Yuan-Yuan; Huang Zhao-Ming; Shi Jie-Long; Li Chun-Fang; Wang Qi
2007-01-01
We have discussed theoretically the negative refraction in finite one-dimensional (1D) photonic crystals (PCs)composed of alternative layers with high index contrast. The frequency bands of negative refraction are obtained with the help of the photonic band structure, the group velocity and the power transmittance, which are all obtained in analytical expression. There shows negative transverse position shift at the endface when negative refraction occurs,which is analysed in detail.
Characterization for defect modes of one-dimensional photonic crystals containing metamaterials
Institute of Scientific and Technical Information of China (English)
Ling Tang; Lei Gao; Jianxing Fang
2008-01-01
Transmission studies for one-dimensional photonic crystals(1DPCs)containing single-negative(SNG)materials inserted with multiple defects are presented.The numbers and positions of the defect modes inside zero-phase(zero-φeff)gap are found to be well characterized by effective medium theory.
Hopman, Wico C.L.; Pottier, Pierre; Yudistira, Didit; Lith, van Joris; Lambeck, Paul V.; De La Rue, Richard M.; Driessen, Alfred; Hoekstra, Hugo J.W.M.; Ridder, de René M.
2005-01-01
We report the fabrication and the characterization of the refractometric and thermo-optical properties of a quasi-one-dimensional waveguide photonic crystal-a strong, 76-micron-long Bragg grating. The transmission spectra (around 660 nm) of the structure have been measured as a function of both the
Coupled optical defect microcavities in one-dimensional photonic crystals and quasi-normal modes
Maksimovic, Milan; Lohmeyer, Manfred; van Groesen, Embrecht W.C.
2008-01-01
We analyze coupled optical defect cavities realized in finite one-dimensional photonic crystals (PC). Viewing these as open systems, where waves are permitted to leave the structures, one obtains eigenvalue problems for complex frequencies (eigenvalues) and quasi-normal modes (QNM) (eigenfunctions).
Hopman, Wico; Pottier, Pierre; Yudistira, Didit; Lith, van Joris; Lambeck, Paul; De La Rue, Richard; Driessen, Alfred; Hoekstra, Hugo J.W.M.; Ridder, de René M.
2004-01-01
A quasi one-dimensional photonic crystal has been fabricated and the applicability of this strong grating for optical sensing has been investigated by measuring the transmission spectra as a function of the cladding refractive index. The cladding index was varied a small range. By monitoring the tra
El-Naggar, Sahar A.
2017-01-01
In this article, we theoretically study electromagnetic waves that propagate in one-dimensional cylindrical photonic crystals (1DCPC) containing single negative materials. We examine the optical properties of three gaps namely; the zero-effective phase (zero- ϕ), the zero-permittivity (zero- ɛ) and the zero-permeability (zero- μ). We calculate the optical reflectance for transverse electric(magnetic) TE(TM) polarizations using the transfer matrix method in the cylindrical coordinates. We study the effect of azimuthal mode number ( m) and the starting radius on these gaps. The results show that the zero- μ (zero- ɛ) gap is found for TE(TM) polarization at frequency where μ( ɛ) changes its sign for m ≥ 1. The width of the gap increases by decreasing the starting radius or by increasing m, whereas the zero- ϕ gap remains invariant. In addition, we present a brief design of 1D-CPC that has a polarization-independent wide gap especially for high azimuthal mode number ( m > 2). Our results can help improve the performance of microwave devices independent of the source wave polarization.
Institute of Scientific and Technical Information of China (English)
Zhanshan Wang; Tian Sang; Fengli Wang; Yonggang Wu; Lingyan Chen
2008-01-01
Band structures of one-dimensional(1D)photonic crystals(PCs)containing dispersive left-handed metamaterials are studied theoretically.The results show that the structure possesses a type of photonic band gap originating from total internal reflection(TIR).In contrast to photonic band gaps corresponding to zero average refractive index and zero phase.the TIR gap exhibits sharp angular effect and has no polarization effect.It should also be noted that band structures of transverse electric(TE) and transverse magnetic(TM) mode waves are exactly the same in the PCs we studied.
Simultaneous Multi-frequency Topological Edge Modes between One-dimensional Photonic Crystals
Choi, Ka Hei; Ling, C. W.; Lee, K. F.; Tsang, Y. H.; Fung, Kin Hung
2016-01-01
We show theoretically that, in the limit of weak dispersion, one-dimensional (1D) binary centrosymmetric photonic crystals can support topological edge modes in all photonic band gaps. By analyzing their bulk band topology, these "harmonic" topological edge modes can be designed in a way that they exist at all photonic band gaps opened at the center of the Brillouin Zone, or at all gaps opened at the zone boundaries, or both. The results may suggest a new approach to achieve robust multi-freq...
Quantum electron plasma in one-dimensional metallic-dielectric photonic crystal
Zverev, N. V.; Yushkanov, A. A.
2017-02-01
The interaction of the electromagnetic radiation with one-dimensional photonic crystal consisting of metal and transparent dielectric medium is studied numerically. Dielectric permeabilities of the electron plasma in the metal are considered both in the quantum Mermin and in the classical Drude-Lorentz approaches. It is shown that the reflection, transmission and absorption-frequency zones of electromagnetic radiation appear in the photonic crystal. In addition, the reflectance, transmittance and absorptance optical coefficients for such photonic crystal in the quantum approach differ from those coefficients in the Drude-Lorentz approach.
Optical properties of periodic, quasi-periodic, and disordered one-dimensional photonic structures
Bellingeri, Michele; Chiasera, Alessandro; Kriegel, Ilka; Scotognella, Francesco
2017-10-01
Photonic structures are building blocks for many optical applications in which light manipulation is required spanning optical filtering, lasing, light emitting diodes, sensing and photovoltaics. The fabrication of one-dimensional photonic structures is achievable with a variety of different techniques, such as spin coating, sputtering, evaporation, pulse laser deposition, or extrusion. Such different techniques enable facile integration of the photonic structure with many types of devices. Photonic crystals are characterized by a spatial modulation of the dielectric constant on the length scale of the wavelength of light giving rise to energy ranges where light cannot propagate through the crystal - the photonic band gap. While mostly photonic crystals are referred to as periodic arrangements, in this review we aim to highlight as well how aperiodicity and disorder affects light modulation. In this review article, we introduce the concepts of periodicity, quasi-periodicity, and disorder in photonic crystals, focussing on the one-dimensional case. We discuss in detail the physical peculiarities, the fabrication techniques, and the applications of periodic, quasi-periodic, and disorder photonic structures, highlighting how the degree of crystallinity matters in the manipulation of light. We report different types of disorder in 1D photonic structures and we discuss their properties in terms of light transmission. We discuss the relationship between the average total transmission, in a range of wavelengths around the photonic band gap of the corresponding photonic crystal, and the homogeneity of the photonic structures, quantified by the Shannon index. Then we discuss the light transmission in structures in which the high refractive index layers are aggregated in clusters following a power law distribution. Finally, in the case of structures in which the high refractive index layers are aggregated in clusters with a truncated uniform distribution, we discuss: i) how
Tolmachev, V. A.
2017-04-01
The theoretical and experimental investigations of photonic band gaps in one-dimensional photonic crystals created by micromatchining silicon, which have been performed by the author as part of his doctoral dissertation, are presented. The most important result of the work is the development of a method of modeling photonic crystals based on photonic band gap maps plotted in structure-property coordinates, which can be used with any optical materials and in any region of electromagnetic radiation, and also for nonperiodic structures. This method made it possible to realize the targeted control of the optical contrast of photonic crystals and to predict the optical properties of optical heterostructures and three-component and composite photonic crystals. The theoretical findings were experimentally implemented using methods of micromatchining silicon, which can be incorporated into modern technological lines for the production of microchips. In the IR spectra of a designed and a fabricated optical heterostructure (a composite photonic crystal), extended bands with high reflectivities were obtained. In a Si-based three-component photonic crystal, broad transmission bands and photonic band gaps in the middle IR region have been predicted and experimentally demonstrated for the first time. Si-liquid crystal periodic structures with electric-field tunable photonic band-gap edges have been investigated. The one-dimensional photonic crystals developed based on micromatchining silicon can serve as a basis for creating components of optical processors, as well as highly sensitive chemical and biological sensors in a wide region of the IR spectrum (from 1 to 20 μm) for lab-on-a-chip applications.
Modified Photoluminescence by Silicon-Based One-Dimensional Photonic Crystal Microcavities
Institute of Scientific and Technical Information of China (English)
CHEN San; QIAN Bo; WEI Jun-Wei; CHEN Kun-Ji; XU Jun; LI Wei; HUANG Xin-Fan
2005-01-01
@@ Photoluminescence (PL) from one-dimensional photonic band structures is investigated. The doped photonic crystal with microcavities are fabricated by using alternating hydrogenated amorphous silicon nitride (a-SiNx :H/aSiNy:H) layers in a plasma enhanced chemical vapour deposition (PECVD) chamber. It is observed that microcavities strongly modify the PL spectra from active hydrogenated amorphous silicon nitride (a-SiNz :H) thin film.By comparison, the wide emission band width 208nm is strongly narrowed to 11 nm, and the resonant enhancement of the peak PL intensity is about two orders of magnitude with respect to the emission of the λ/2-thick layer of a-SiNz:H. A linewidth of △λ = 11 nm and a quality factor of Q = 69 are achieved in our one-dimensional a-SiNz photonic crystal microcavities. Measurements of transmittance spectra of the as-grown samples show that the transmittance resonant peak of a cavity mode at 710 nm is introduced into the band gap of one-dimensional photonic crystal distributed Bragg reflector (DBR), which further verifies the microcavity effects.
Controllable scattering of photons in a one-dimensional resonator waveguide
Sun, C. P.; Zhou, L.; Gong, Z. R.; Liu, Y. X.; Nori, F.
2009-03-01
We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. [4pt] L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons in a 1D resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). URL: http://link.aps.org/abstract/PRL/v101/e100501
Magneto-tunable one-dimensional graphene-based photonic crystal
Energy Technology Data Exchange (ETDEWEB)
Jahani, D., E-mail: dariush110@gmail.com; Soltani-Vala, A., E-mail: asoltani@tabrizu.ac.ir; Barvestani, J.; Hajian, H. [Department of Solid State Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of)
2014-04-21
We investigate the effect of a perpendicular static magnetic field on the optical bandgap of a one-dimensional (1D) graphene-dielectric photonic crystal in order to examine the possibility of reaching a rich tunable photonic bandgap. The solution of the wave equation in the presence of the anisotropic Hall situation suggests two decoupled circularly polarized wave each exhibiting different degrees of bandgap tunability. It is also numerically demonstrated that applying different values of field intensity lead to perceptible changes in photonic bandgap of such a structure. Finally, the effect of opening a finite electronic gap in the spectrum of graphene on the optical dispersion solution of such a 1D photonic crystal is reported. It is shown that increasing the value of the electronic gap results in the shrinkage of the associated photonic bandgaps.
Light propagation in tunable exciton-polariton one-dimensional photonic crystals
Sedov, E S; Arakelian, S M; Kavokin, A V
2016-01-01
Simulations of propagation of light beams in specially designed multilayer semiconductor structures (one-dimensional photonic crystals) with embedded quantum wells reveal characteristic optical properties of resonant hyperbolic metamaterials. A strong dependence of the refraction angle and the optical beam spread on the exciton radiative lifetime is revealed. We demonstrate the strong negative refraction of light and the control of the group velocity of light by an external bias through its effect upon the exciton radiative properties.
Light propagation in tunable exciton-polariton one-dimensional photonic crystals
Sedov, E. S.; Cherotchenko, E. D.; Arakelian, S.M.; Kavokin, A. V.
2016-01-01
Simulations of propagation of light beams in specially designed multilayer semiconductor structures (one-dimensional photonic crystals) with embedded quantum wells reveal characteristic optical properties of resonant hyperbolic metamaterials. A strong dependence of the refraction angle and the optical beam spread on the exciton radiative lifetime is revealed. We demonstrate the strong negative refraction of light and the control of the group velocity of light by an external bias through its e...
Localized Mode Enhanced Coupler Based on Quasi-One-Dimensional Photonic Crystal Microstrip
Institute of Scientific and Technical Information of China (English)
LI Yun-Hui; JIANG Hai-Tao; HE Li; LI Hong-Qiang; ZHANG Ye-Wen; CHEN Hong
2004-01-01
We propose a novel localized mode enhanced (LME) coupler based on quasi-one-dimensional photonic crystal microstrips, which is promising to be applied in wavelength division multiplexed microwave communication systems. Compared to the traditional microstrip coupler, the LME structure has two advantages: high efficiency and frequency selectivity. Even in a relatively far coupling distance, this structure can still achieve a high efficiency about 50%. The frequency selectivity can be realized by simply tuning the distance between two transmission lines.
Multi-channel and sharp angular spatial filters based on one-dimensional photonic crystals
Institute of Scientific and Technical Information of China (English)
Shaoji Jiang; Jianrong Li; Jijia Tang; Hezhou Wang
2006-01-01
A photonic heterostructure with multi-channel and sharp angular defect modes by combining two different one-dimensional defective photonic crystals is proposed. The filters designed on the basis of this heterostructure possess both functions of multi-channel narrow band filtering and sharp angular filtering.The channels, channel interval, and number of channels can be tuned by adjusting the geometric and physical parameters of the heterostuctures. This kind of filters will benefit the development of multi-channel interstellar or atmosphere optical communication.
Schilke, Alexander; Guerin, William
2012-01-01
We experimentally study the photonic properties of a cold-atom sample trapped in a one-dimensional optical lattice under the conditions of electromagnetically induced transparency. We show that such a medium has two photonic band gaps. One of them is in the transparency window and gives rise to a Bragg mirror, which is spectrally very narrow and dynamically tunable. We discuss the advantages and the limitations of this system. As an illustration of a possible application we demonstrate a two-port all-optical switch.
Broadband wave plates: Approach from one-dimensional photonic crystals containing metamaterials
Energy Technology Data Exchange (ETDEWEB)
Chen Yihang, E-mail: kallenmail@sina.co [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)
2011-02-14
Broadband wave plates working in subwavelength scale are realized by one-dimensional photonic crystals containing negative-index materials. It is demonstrated that the phase shift of reflected wave as a function of frequency changes smoothly within the stop band of the photonic crystal, while it changes sharply within the pass band. In the stop band, the difference between the phase of TE and that of TM reflected wave could remain constant in a rather wide frequency range. These properties are useful for designing compact wave plates or phase retarders which can be used in broad spectral bandwidth.
Time-dependent Bragg diffraction and short-pulse reflection by one-dimensional photonic crystals
André, Jean-michel
2015-01-01
The time-dependence of the Bragg diffraction by one-dimensional photonic crystals and its influence on the short pulse reflection are studied in the framework of the coupled- wave theory. The indicial response of the photonic crystal is calculated and it appears that it presents a time-delay effect with a transient time conditioned by the extinction length. A numerical simulation is presented for a Bragg mirror in the x-ray domain and a pulse envelope modelled by a sine-squared shape. The potential consequences of the time-delay effect in time-dependent optics of short-pulses are emphasized.
Energy Technology Data Exchange (ETDEWEB)
Gonchar, K. A., E-mail: k.a.gonchar@gmail.com [Moscow State University, Physics Faculty (Russian Federation); Musabek, G. K.; Taurbayev, T. I. [Al Farabi Kazakh National University, Physics Department (Kazakhstan); Timoshenko, V. Yu. [Moscow State University, Physics Faculty (Russian Federation)
2011-05-15
In porous-silicon-based multilayered structures that exhibit the properties of one-dimensional photonic crystals, an increase in the photoluminescence and Raman scattering intensities is observed upon optical excitation at the wavelength 1.064 {mu}m. When the excitation wavelength falls within the edge of the photonic band gap of the structures, a multiple increase (by a factor larger than 400) in the efficiency of Raman scattering is detected. The effect is attributed to partial localization of excitation light and, correspondingly, to the much longer time of interaction of light with the material in the structures.
Photon scattering by a three-level emitter in a one-dimensional waveguide
Witthaut, D
2010-01-01
We discuss the scattering of photons from a three-level emitter in a one-dimensional waveguide, where the transport is governed by the interference of spontaneously emitted and directly transmitted waves. The scattering problem is solved in closed form for different level structures. Several possible applications are discussed: The state of the emitter can be switched deterministically by Raman scattering, thus enabling applications in quantum computing such as a single photon transistor. An array of emitters gives rise to a photonic band gap structure, which can be tuned by a classical driving laser. A disordered array leads to Anderson localization of photons, where the localization length can again be controlled by an external driving.
Vovchenko, Ludmila; Lozitsky, Oleg; Sagalianov, Igor; Matzui, Ludmila; Launets, Vilen
2017-04-01
This work presents the results of computer modeling and experimental measurements of microwave transmission properties for one-dimensional periodic multi-layered photonic structures (PCs), composed of epoxy layers and composite layers filled with nanocarbon particles—multi-walled carbon nanotubes and graphite nanoplatelets. The results show that the characteristics of observed photonic band gaps in transmission spectra of PC can be controlled by varying the parameters of layers, namely, the complex permittivity and the layer thickness. It was found that the insertion of the defects (for instance, magnetic layer) into photonic structure can change the EMR transmission spectrum. The comparative analysis of EMR transmission spectra for investigated photonic structures has showed good agreement between the experimental and simulated data. It was found that EMR absorption in composite layers of photonic structures shifts the transmission spectra to the smaller values of EMR transmission index and reduces the sharpness of photonic band gaps. Thus, by changing the parameters of composite layers in photonic structure, we can obtain the tunable photonic band gaps, necessary for technological applications in devices, capable of storing, guiding, and filtering microwaves.
Band structure of one-dimensional plasma photonic crystals using the Fresnel coefficients method
Jafari, A.; Rahmat, A.
2016-11-01
The current study has examined the band structures of two types of photonic crystals (PCs). The first is a one-dimensional metamaterial photonic crystal (1DMMPC) composed of double-layered units for which both layers of each unit are dielectric. The second type is a very similar one-dimensional plasma photonic crystal (1DPPC) also composed of double-layered units in which the first layer is a dielectric material but the second is a plasma layer. This study compares the band structures of the 1DMMPC with specific optical characteristics of the 1DPPC using the Fresnel coefficients method and also compares the results of this method with the results of the transfer matrix method. It is concluded that the dependency of the electric permittivity of the plasma layer on the incident field frequency causes differences in the band structures in 1DMMPC and 1DPPC for both TE and TM polarizations and their gaps reside in different frequencies. The band structures of the 1DMMPC and 1DPPC are confirmed by the results of the transfer matrix method.
Tolmachev, V; Perova, T; Moore, R
2005-10-17
A method of photonic band gap extension using mixing of periodic structures with two or more consecutively placed photonic crystals with different lattice constants is proposed. For the design of the structures with maximal photonic band gap extension the gap map imposition method is utilised. Optimal structures have been established and the gap map of photonic band gaps has been calculated at normal incidence of light for both small and large optical contrast and at oblique incidence of light for small optical contrast.
Design and optimization of one-dimensional photonic crystals for thermophotovoltaic applications.
Celanovic, Ivan; O'Sullivan, Francis; Ilak, Milos; Kassakian, John; Perreault, David
2004-04-15
We explore the optical characteristics and fundamental limitations of one-dimensional (1D) photonic crystal (PhC) structures as means for improving the efficiency and power density of thermophotovoltaic (TPV) and microthermophotovoltaic (MTPV) devices. We analyze the optical performance of 1D PhCs with respect to photovoltaic diode efficiency and power density. Furthermore, we present an optimized dielectric stack design that exhibits a significantly wider stop band and yields better TPV system efficiency than a simple quarter-wave stack. The analysis is done for both TPV and MTPV devices by use of a unified modeling framework.
Directory of Open Access Journals (Sweden)
Ryotaro Ozaki
2015-09-01
Full Text Available Polarization characteristics of defect mode peaks in a one-dimensional (1D photonic crystal (PC with a nematic liquid crystal (NLC defect layer have been investigated. Two different polarized defect modes are observed in a stop band. One group of defect modes is polarized along the long molecular axis of the NLC, whereas another group is polarized along its short axis. Polarizations of the defect modes can be tuned by field-induced in-plane reorientation of the NLC in the defect layer. The polarization properties of the 1D PC with the NLC defect layer is also investigated by the finite difference time domain (FDTD simulation.
Analysis of cutoff frequency in a one-dimensional superconductor-metamaterial photonic crystal
Aly, Arafa H.; Aghajamali, Alireza; Elsayed, Hussein A.; Mobarak, Mohamed
2016-09-01
In this paper, using the two-fluid model and the characteristic matrix method, we investigate the transmission characteristics of the one-dimensional photonic crystal. Our structure composed of the layers of low-temperature superconductor material (NbN) and double-negative metamaterial. We target studying the effect of many parameters such as the thickness of the superconductor material, the thickness of the metamaterial layer, and the operating temperature. We show that the cut-off frequency can be tuned efficiently by the operating temperature as well as the thicknesses of the constituent materials.
Enhanced nonlinear optical response of one-dimensional metal-dielectric photonic crystals.
Lepeshkin, Nick N; Schweinsberg, Aaron; Piredda, Giovanni; Bennink, Ryan S; Boyd, Robert W
2004-09-17
We describe a new type of artificial nonlinear optical material composed of a one-dimensional metal-dielectric photonic crystal. Because of the resonant nature of multiple Bragg reflections, the transmission within the transmission band can be quite large, even though the transmission through the same total thickness of bulk metal would be very small. This procedure allows light to penetrate into the highly nonlinear metallic layers, leading to a large nonlinear optical response. We present experimental results for a Cu/SiO(2) crystal which displays a strongly enhanced nonlinear optical response (up to 12X) in transmission.
Institute of Scientific and Technical Information of China (English)
WANG Tao; LI Qing; GAO DingShan
2009-01-01
All-optical switch with the ultrafast optical switching rate is a key device in the next generation optical network. In this article, we propose a polarization switch with ps switching time, which is constructed from one-dimensional resonant photonic crystal (1D RPC). The model of switch operating at 1.5 μm is established based on the optical stark effect (OSE). We calculate the performance indices of the switch and the influences of errors of periods and refractive index on the performance characteristics.
UV-modulated one-dimensional photonic-crystal resonator for visible lights
Yang, S. Y.; Yang, P. H.; Liao, C. D.; Chieh, J. J.; Chen, Y. P.; Horng, H. E.; Hong, Chin-Yih; Yang, H. C.
2006-12-01
The one-dimensional photonic-crystal (A/SiO2)6/ZnO/(SiO2/A)6 resonators at visible lights are fabricated and characterized, where A may be ZnO or indium tin oxide. Owing to the absorption of ultraviolet (UV) light by the ZnO layers, the refractive index of ZnO layers is changed temporally. This fact led to a temporary shifting of the forbidden band and the resonant mode of the resonator under UV irradiation. Besides, via adjusting the thickness of the ZnO defect layer, the resonant wavelength is manipulated. These experimental data show good consistence with simulated results.
Temporal coupled mode analysis of one-dimensional magneto-photonic crystals with cavity structures
Saghirzadeh Darki, Behnam; Zeidaabadi Nezhad, Abolghasem; Firouzeh, Zaker Hossein
2016-12-01
In this paper, we propose the time-dependent coupled mode analysis of one-dimensional magneto-photonic crystals including one, two or multiple defect layers. The performance of the structures, namely the total transmission, Faraday rotation and ellipticity, is obtained using the proposed method. The results of the developed analytic approach are verified by comparing them to the results of the exact numerical transfer matrix method. Unlike the widely used numerical method, our proposed analytic method seems promising for the synthesis as well as the analysis purposes. Moreover, the proposed method has not the restrictions of the previously examined analytic methods.
Study on optical gain of one-dimensional photonic crystals with active impurity
Institute of Scientific and Technical Information of China (English)
Zhenghua Li; Tinggen Shen; Xuehua Song; Junfeng Ma; Yong Sheng; Gang Wang
2007-01-01
Localized fields in the defect mode of one-dimensional photonic crystals with active impurity are studied with the help of the theory of spontaneous emission from two-level atoms embedded in photonic crystals.Numerical simulations demonstrate that the enhancement of stimulated radiation, as well as the phenomena of transmissivity larger than unity and the abnormality of group velocity close to the edges of photonic band gap, are related to the negative imaginary part of the complex effective refractive index of doped layers. This means that the complex effective refractive index has a negative imaginary part, and that the impurity state with very high quality factor and great state density will occur in the photonic forbidden band if active impurity is introduced into the defect layer properly. Therefore, the spontaneous emission can be enhanced, the amplitude of stimulated emission will be very large and it occurs most probably close to the edges of photonic band gap with the fundamental reason, the group velocity close to the edges of band gap is very small or abnormal.
Vectorial coupled-mode solitons in one-dimensional photonic crystals
Institute of Scientific and Technical Information of China (English)
朱善华; 黄国翔; 崔维娜
2002-01-01
We study the dynamics of vectorial coupled-mode solitons in one-dimensional photonic crystals with quadraticand cubic nonlinearities. Starting from Maxwell's equations, the vectorial coupled-mode equations for the envelopesof two fundamental-frequency optical mode and one low-frequency mode components due to optical rectification arederived by means of the method of multiple scales. A set of coupled soliton solutions of the vectorial coupled-modeequations is provided. The results show that a modulation of the fundamental-frequency optical modes occurs due tothe optical rectification field resulting from the quadratic nonlinearity. The optical rectification field disappears whenthe frequency of the fundamental-frequency optical fields approaches the edge of the photonic bands.
Institute of Scientific and Technical Information of China (English)
Bing Chen; Lin Huang; Yongdong Li; Chunliang Liu; Guizhong Liu
2012-01-01
A fundamental 1 ×2 beam splitter based on the self-imaging phenomena in multi-mode one-dimensional (1D) photonic crystal (PC) waveguides is presented,and its transmission characteristics are investigated using the finite-difference time-domain method.Calculated results indicate that a high transmittance (＞95％) can be observed within a wide frequency band for the 1×2 beam splitter without complicated structural optimizations.In this letter,a simple and compact 1 ×4 beam splitter is constructed by combining the fundamental 1 ×2 beam splitter with the flexible bends of 1D PC waveguides.Such beam splitters can be applied to highly dense photonic integrated circuits.
Surface polaritons of one-dimensional photonic crystals containing graphene monolayers
Madani, Amir; Roshan Entezar, Samad
2014-11-01
We investigated theoretically the existence of surface polaritons (SPs) at the interface of a one-dimensional photonic crystal containing graphene monolayers. It is shown that the structure has a new type of the photonic band gap in the THz region which is strictly omnidirectional for the TM-polarization and can support the SPs for both TM-polarization and TE-polarization. The results show that the characteristics of the SPs depends on the optical properties of the graphene sheets which can be controlled by a gate voltage. We plotted the electromagnetic field profiles of the SPs at the frequency range of the graphene induced band gap and a conventional Bragg gap of the structure. It is found that the SPs at the graphene induced band gap are more localized than the SPs at the Bragg gaps.
Theory of Pulsed Four-Wave-Mixing in One-dimensional Silicon Photonic Crystal Slab Waveguides
Lavdas, Spyros
2015-01-01
We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general set-up of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects such as self- and cross-phase modulation (SPM, XPM), two-photon absorption (TPA), and cross-absorption modulation (XAM), as well as the coupled dynamics of FCs and optical field. In particular, our theoretical analysis based on the coupled-mode theory provides rigorously derived formulae for linear dispersion coefficients of the guiding modes, linear coupling coefficients between these modes, as well as the nonlinear waveg...
Madani, Amir; Entezar, Samad Roshan
2015-10-01
Theoretically, the Goos-Hänchen effect at the interface of a one-dimensional photonic crystal containing graphene monolayers has been investigated. It was shown that the lateral shift of the reflected beam can be remarkably enhanced when the phase matching conditions are satisfied for the excitation of the surface polaritons at the interface of the structure in the graphene induced photonic band gap. The effect of the optical properties of the graphene sheets on the enhancement of the Goos-Hänchen shift was investigated and it was shown that the beam displacement can be controlled by the tuning of the chemical potential of graphene. This may have potential applications in the optical communication systems.
Laser emissions from one-dimensional photonic crystal rings on silicon-dioxide
Lu, Tsan-Wen; Tsai, Wei-Chi; Wu, Tze-Yao; Lee, Po-Tsung
2013-02-01
In this report, we design and utilize one-dimensional photonic crystal ring resonators (1D PhCRRs) to realize InGaAsP/SiO2 hybrid lasers via adhesive bonding technique. Single-mode lasing with low threshold from the dielectric mode is observed. To further design a nanocavity with mode gap effect in 1D PhCRR results in the reduced lasing threshold and increased vertical laser emissions, owing to the reduced dielectric mode volume and the broken rotational symmetry by the nanocavity. Such hybrid lasers based on 1D PhC rings provides good geometric integration ability and new scenario for designing versatile devices in photonic integrated circuits.
Theory of pulsed four-wave mixing in one-dimensional silicon photonic crystal slab waveguides
Lavdas, Spyros; Panoiu, Nicolae C.
2016-03-01
We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general setup of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects such as self- and cross-phase modulation (SPM, XPM), two-photon absorption (TPA), and cross-absorption modulation (XAM), as well as the coupled dynamics of free-carriers FCs and optical field. In particular, our theoretical analysis based on the coupled-mode theory provides rigorously derived formulas for linear dispersion coefficients of the guiding modes, linear coupling coefficients between these modes, as well as the nonlinear waveguide coefficients describing SPM, XPM, TPA, XAM, and FWM. In addition, our theoretical analysis and numerical simulations reveal key differences between the characteristics of FWM in the slow- and fast-light regimes, which could potentially have important implications to the design of ultracompact active photonic devices.
Madani, Amir; Entezar, Samad Roshan
2017-07-01
The transmission properties of a one-dimensional photonic crystal made of alternate layers of an isotropic ordinary dielectric and a graphene-based hyperbolic metamaterial are studied theoretically using the transfer matrix method. The metamaterial layers show hyperbolic dispersion in certain frequency range and are considered as an anisotropic effective medium in which the optical axis is normal to the graphene layers. It is shown that the structure has some photonic band gaps in both the hyperbolic and elliptical frequency regions of the hyperbolic metamaterial layers, which are tunable by changing the chemical potential of the graphene monolayers. Moreover, the characteristics of the transverse-magnetic (TM)-polarized photonic band gaps remarkably depend on the orientation of the optical axis of the hyperbolic metamaterial layers. It is found that the electric field intensity of the propagating modes from the hyperbolic metamaterial frequency region is concentrated in the high-index isotropic layers and the electric field intensity of the propagating modes from the elliptical frequency region is concentrated in the low-index anisotropic layers.
Optical properties of one-dimensional Fibonacci quasi-periodic graphene photonic crystal
Zhang, Yuping; Wu, Zhixin; Cao, Yanyan; Zhang, Huiyun
2015-03-01
We propose a novel type of one-dimensional photonic crystal called Fibonacci quasi-periodic graphene photonic crystal (FGPC), in which the structure in each dielectric cell follows the Fibonacci sequence and the graphene monolayers are embedded between adjacent dielectric layers. The transmission properties of FGPC are investigated using transfer matrix method in detail. It is shown that both photonic band gap induced by graphene (GIBPG) and the Bragg gap exist in the structure. We study the band gaps of TE and TM waves at different incident angles or chemical potentials. It is found that the band gaps can be tuned via a gate voltage and GIBPG is almost omnidirectional and insensitive to the polarization. In order to investigate difference between the GIPBG and Bragg gap, we plot the electromagnetic field profiles inside FGPC for some critical frequencies. The propagation loss of the structure caused by absorption of graphene is researched in detail. Also, the passing bands of Fibonacci sequences of different orders and their splitting behavior at higher order are investigated.
Ardakani, Abbas Ghasempour
2014-12-20
We propose a one-dimensional conjugated photonic crystal single heterojunction infiltrated with a single graphene layer to achieve large Faraday rotation (FR) angles as well as high transmission simultaneously. The effects of the external magnetic field values, incidence angle, number of unit cells, layer thickness of constituents of the conjugated photonic crystals, chemical potential of graphene, and ambient temperature on the Faraday rotation angle and transmission are investigated. Our results reveal that both the sign reversal and shifting of the FR peak can be obtained by changing the width of layers in the conjugated photonic crystal. In the case of negative FR angle, an increase of magnetic field enhances the FR angle and degrades the transmission. However, in the case of positive FR angle, when the magnetic field increases to a certain value, the FR angle is improved too. Further increase of the magnetic field leads to a decrease of FR angle. With increasing the number of unit cells, the FR angle is enhanced at the cost of decreasing the transmission. It is shown that normal incidence results in higher FR angle and transmission. It is also demonstrated that sign reversal and change of the FR angle is possible by manipulating the chemical potential of graphene and the ambient temperature.
Singh, Bipin K.; Kumar, Pawan; Pandey, Praveen C.
2014-12-01
We have demonstrated control of the photonic band gaps (PBGs) in 1-D photonic crystals using linear graded index material. The analysis of PBG has been done in THz region by considering photonic crystals in the form of ten periods of second, third and fourth generation of the Fibonacci sequence as unit cell. The unit cells are constituted of two kinds of layers; one is taken of linear graded index material and other of normal dielectric material. For this investigation, we used a theoretical model based on transfer matrix method. We have obtained a large number of PBGs and their bandwidths can be tuned by changing the grading profile and thicknesses of linear graded index layers. The number of PBGs increases with increase in the thicknesses of layers and their bandwidths can be controlled by the contrast of initial and final refractive index of the graded layers. In this way, we provide more design freedom for photonic devices such as reflectors, filters, optical sensors, couplers, etc.
The ballistic dimer resonance in the one-dimensional disordered photonic crystals
Khalfoun, H.; Bentata, S.; Bouamoud, M.; Henrard, L.; Vandenbem, C.
2009-12-01
The propagation of electromagnetic waves in one-dimensional disordered dielectric layer stack is studied theoretically using the transfer matrix formalism. The presence of the dimer unit cells inside a host photonic crystal, as the intentionally short range disorder correlation, provides predicted dimer resonances, leading to the break down of the Anderson localization. However while suitably adjusting the intrinsic defect unit cell parameters (i.e. the defect dielectric constants), the light can be transmitted on larger localization length through a ballistic canal, opening up possibilities for performing better tailored ballistic optical filters. Moreover, by increasing the rate of disorder (i.e. the defects concentration and/or the length of the system) the quality of the transmission around the ballistic resonance can be improved with the smoother corresponding allowed mini bands.
Wide Range Temperature Sensors Based on One-Dimensional Photonic Crystal with a Single Defect
Directory of Open Access Journals (Sweden)
Arun Kumar
2012-01-01
Full Text Available Transmission characteristics of one-dimensional photonic crystal structure with a defect have been studied. Transfer matrix method has been employed to find the transmission spectra of the proposed structure. We consider a Si/air multilayer system and refractive index of Si layer has been taken as temperature dependent. As the refractive index of Si layer is a function of temperature of medium, so the central wavelength of the defect mode is a function of temperature. Variation in temperature causes the shifting of defect modes. It is found that the average change or shift in central wavelength of defect modes is 0.064 nm/K. This property can be exploited in the design of a temperature sensor.
Impurity effects on the band structure of one-dimensional photonic crystals: Experiment and theory
Luna-Acosta, G A; Kuhl, U; Stoeckmann, H -J
2007-01-01
We study the effects of single impurities on the transmission in microwave realizations of the photonic Kronig-Penney model, consisting of arrays of Teflon pieces alternating with air spacings in a microwave guide. As only the first propagating mode is considered, the system is essentially one dimensional obeying the Helmholtz equation. We derive analytical closed form expressions from which the band structure, frequency of defect modes, and band profiles can be determined. These agree very well with experimental data for all types of single defects considered (e. g. interstitial, substitutional) and shows that our experimental set-up serves to explore some of the phenomena occurring in more sophisticated experiments. Conversely, based on the understanding provided by our formulas, information about the unknown impurity can be determined by simply observing certain features in the experimental data for the transmission. Further, our results are directly applicable to the closely related quantum 1D Kronig-Penn...
Gorelik, V. S.; Klimonsky, S. O.; Filatov, V. V.; Napolskii, K. S.
2016-04-01
The optical properties of one-dimensional photonic crystals based on porous anodic aluminum oxide films have been studied by measuring transmittance and specular reflectance spectra in the visible and UV spectral regions. Angular dependences of the spectral positions of optical stop bands are obtained. It is shown that the reflectance within the first stop band varies from point to point on the sample surface, reaching a level of 98-99% at some points. The dispersion relation for electromagnetic waves in the model of infinite periodic structure is calculated for the samples under study. The possibility of using models with an infinite or finite number of layers to calculate reflectance spectra near the first optical stop band is discussed.
Impurity effects on the band structure of one-dimensional photonic crystals: experiment and theory
Energy Technology Data Exchange (ETDEWEB)
Luna-Acosta, G A [Instituto de Fisica, BUAP Apartado Postal J-48, 72570 Puebla (Mexico); Schanze, H; Kuhl, U; Stoeckmann, H-J [Fachbereich Physik der Philipps-Universitaet Marburg, Renthof 5, D-35032 (Germany)], E-mail: gluna@sirio.ifuap.buap.mx
2008-04-15
We study the effects of single impurities on the transmission in microwave realizations of the photonic Kronig-Penney model, consisting of arrays of Teflon pieces alternating with air spacings in a microwave guide. As only the first propagating mode is considered, the system is essentially one-dimensional (1D) obeying the Helmholtz equation. We derive analytical closed form expressions from which the band structure, frequency of defect modes and band profiles can be determined. These agree very well with experimental data for all types of single defects considered (e.g. interstitial and substitutional) and show that our experimental set-up serves to explore some of the phenomena occurring in more sophisticated experiments. Conversely, based on the understanding provided by our formulae, information about the unknown impurity can be determined by simply observing certain features in the experimental data for the transmission. Further, our results are directly applicable to the closely related quantum 1D Kronig-Penney model.
The effect of temperature on one-dimensional nanometallic photonic crystals with coupled defects
Indian Academy of Sciences (India)
ABDOLRASOUL GHARAATI; ZEINAB ZARE
2017-05-01
Using the transfer matrix method, the effect of temperature on one-dimensional (1D) nanostructure photonic crystal with coupled defects has been investigated. One of the layers of this structure is silver. The complex refractive index of silver is dependent on temperature and wavelength. This structure is tunable with temperature and incident angle. It is found that the number of defect modes is equal to the number of coupled defects in all incident angles for both polarizations. Also by increasing the temperature, due to dissipation, the wavelength of the defect modes increases and the height of the defect modes decreases. The wavelengths of defect modes depend linearly on temperature for both polarizations in all incident angles.
Spectral properties of a one-dimensional photonic crystal with a resonant defect nanocomposite layer
Energy Technology Data Exchange (ETDEWEB)
Vetrov, S. Ya., E-mail: s.vetrov@inbox.ru; Avdeeva, A. Yu., E-mail: avdeeva-anstasiya@yandex.ru [Siberian Federal University (Russian Federation); Timofeev, I. V. [Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Branch (Russian Federation)
2011-11-15
The spectral properties of a one-dimensional photonic crystal with a defect nanocomposite layer that consists of metallic nanoballs distributed in a transparent matrix and is characterized by an effective resonance permittivity are studied. The problem of calculating the transmission, reflection, and absorption spectra of p-polarized waves in such structures is solved for oblique incidence of light, and the spectral manifestation of defect-mode splitting as a function of the volume fraction of nanoballs and the structural parameters is studied. The splitting is found to depend substantially on the nanoball concentration in the defect, the defect layer thickness, and the angle of incidence. The angle of incidence is found at which the resonance frequency of the nanocomposite is located near the edge of the bandgap or falls in the frequency region of a continuous spectrum. The resonance situation appearing in this case results in an additional transmission band or an additional bandgap in the transmission spectrum.
Transmission spectra of one-dimensional photonic crystals including negative-refractive-index media
Institute of Scientific and Technical Information of China (English)
SHEN Xiao-ming; CHEN Xian-feng; JIANG Mei-ping; SHI Du-fang
2005-01-01
We introduce a new model of one-dimensional (1D) photonic crystal composed of alternately arranged RHM and LHM layers with positive and negative refractive indices respectively, for which the transmission spectra of the model are calculated numerically with the transfer matrix method, and the band-gap structure and the polarization properties are analyzed. We found that the introduction of negative refractive index layers (i.e.LHM medium layers) gives rise to some peculiar band-gap structure and polarization properties as follows. Firstly, the forbidden bands are extremely wide and the transmission bands are very sharp without oscillation;and secondly, the change of incident angle has different influences on the forbidden bands of TE and TM modes. For the TM mode, the forbidden band width decreases substantially and finally vanishes, and for the TE mode with central wavelength, the total reflection happens at any incident angle.
Analysis and synthesis of one-dimensional magneto-photonic crystals using coupled mode theory
Saghirzadeh Darki, Behnam; Nezhad, Abolghasem Zeidaabadi; Firouzeh, Zaker Hossein
2017-03-01
We utilize our previously developed temporal coupled mode approach to investigate the performance of one-dimensional magneto-photonic crystals (MPCs). We analytically demonstrate that a double-defect MPC provides adequate degrees of freedom to design a structure for arbitrary transmittance and Faraday rotation. By using our developed analytic approach along with the numerical transfer matrix method, we present a procedure for the synthesis of an MPC to generate any desired transmittance and Faraday rotation in possible ranges. However it is seen that only discrete values of transmittance and Faraday rotation are practically obtainable. To remedy this problem along with having short structures, we introduce a class of MPC heterostructures which are combinations of stacks with high and low optical contrast ratios.
Analysis of cutoff frequency in one dimensional ternary superconducting photonic crystal
K. P., Sreejith; Maria D'souza, Nirmala; Mathew, Vincent
2017-09-01
By means of two fluid model and transfer matrix method, we have theoretically investigated the transmittance property of a one dimensional ternary photonic crystal consist of a pair of superconducting materials and a dielectric in the infrared frequency region. We mainly focus on the analysis of cutoff frequency since the calculations can be useful in the fabrication of optical devices such as reflector, high pass filter etc. The study reveals that the cutoff frequency is sensitive to thickness of superconducting materials, dielectric layer thickness, operating temperature and refractive index of intermediate dielectric. Cutoff frequency shifted to higher frequency region on increasing number of periods and superconductor layer thickness where as it reduces on increasing dielectric thickness, operating temperature and refractive index of intermediate dielectric. Furthermore, we compared the cutoff frequency of three different 1D ternary photonic crystals comprising of a dielectric and a pair of high-high, high-low and low-low temperature superconducting materials. Our comparison results shows that the cutoff frequency can be effectively modified with different combination of superconducting materials.
Miao, Lei; Shi, Jiaming; Wang, Jiachun; Zhao, Dapeng; Chen, Zongsheng; Wang, Qichao
2016-05-01
The characteristic matrix method in thin-film optical theory was used to calculate heterogeneous doped one-dimensional photonic crystals (1-D PCs), which were fabricated by alternate deposition of Te, ZnSe, and Si materials on a silicon wafer. The heterogeneous structure was adopted to broaden the photonic band gap, within which the low reflection valley was achieved by doping. Infrared spectrum tests showed that the average emissivities of the 1-D PC were 0.0845 and 0.281, corresponding, respectively, to the bands of 3 to 5 and 8 to 14 μm. Moreover, the emissivity was 0.45 over the 5 to 8 μm nonatmospheric window, and the reflectivity was 0.28 at the wavelength of 10.6 μm. The results indicated that the heterogeneous doped 1-D PC was able to selectively achieve low emissivities over infrared atmospheric windows and a low reflectivity for the CO2 laser, which exhibited remarkable competence in compatible infrared and laser stealth applications.
Liu, Jingyi; Zhang, Wenzhao; Li, Xun; Yan, Weibin; Zhou, Ling
2016-10-01
We investigate the two-photon transport properties inside one-dimensional waveguide side coupled to an atom-optomechanical system, aiming to control the two-photon transport by using the nonlinearity. By generalizing the scheme of Phys. Rev. A 90, 033832, we show that Kerr nonlinearity induced by the four-level atoms is remarkable and can make the photons antibunching, while the nonlinear interaction of optomechanical coupling participates in both the single photon and the two photon processes so that it can make the two photons exhibiting bunching and antibunching.
Out-of-plane nanomechanical tuning of double-coupled one-dimensional photonic crystal cavities.
Tian, Feng; Zhou, Guangya; Du, Yu; Chau, Fook Siong; Deng, Jie; Akkipeddi, Ramam
2013-06-15
We demonstrate tuning of double-coupled one-dimensional photonic crystal cavities by their out-of-plane nanomechanical deformations. The coupled cavities are pulled by the vertical electrostatic force generated by the potential difference between the device layer and the handle layer in a silicon-on-insulator chip, and the induced deformations are analyzed by the finite element method. Applied with a voltage of 12 V, the cavities obtain a redshift of 0.0405 nm (twice the linewidth) for their second-order odd resonance mode and a blueshift of 0.0635 nm (three times the linewidth) for their second-order even resonance mode, which are mainly attributed to out-of-plane relative displacement. Out-of-plane tuning of coupled cavities does not need actuators and corresponding circuits; thus the device is succinct and compact. This working principle can be potentially applied in chip-level optoelectronic devices, such as sensors, switches, routers, and tunable filters.
Analysis of cutoff frequency in a one-dimensional superconductor-metamaterial photonic crystal
Energy Technology Data Exchange (ETDEWEB)
Aly, Arafa H, E-mail: arafa16@yahoo.com [Department of Physics, Faculty of Sciences, Beni-Suef University (Egypt); Aghajamali, Alireza [Department of Physics, Marvdasht Branch, Islamic Azad University, Marvdasht (Iran, Islamic Republic of); Elsayed, Hussein A.; Mobarak, Mohamed [Department of Physics, Faculty of Sciences, Beni-Suef University (Egypt)
2016-09-15
Highlights: • Our results show that the appearance of the cutoff frequency, below which the incident electromagnetic waves cannot propagate in the structure. We demonstrate that the cutoff frequency shows an upward trend as the thickness of the superconductor layer as well as the thickness of the metamaterial increase. • The cutoff frequency can be tuned by the operating temperature. Our structures are good candidates for many optical devices such as optical filters, switches, temperature controlled optical shutter, and among photoelectronic applications in gigahertz. - Abstract: In this paper, using the two-fluid model and the characteristic matrix method, we investigate the transmission characteristics of the one-dimensional photonic crystal. Our structure composed of the layers of low-temperature superconductor material (NbN) and double-negative metamaterial. We target studying the effect of many parameters such as the thickness of the superconductor material, the thickness of the metamaterial layer, and the operating temperature. We show that the cut-off frequency can be tuned efficiently by the operating temperature as well as the thicknesses of the constituent materials.
Directory of Open Access Journals (Sweden)
Mahshid Mokhtarnejad
2017-01-01
Full Text Available This study examined MQWs made of InGaAs/GaAs, InAlAs/InP, and InGaAs/InP in terms of their band structure and reflectivity. We also demonstrated that the reflectivity of MQWs under normal incident was at maximum, while both using a strong pump and changing incident angle reduced it. Reflectivity of the structure for a weak probe pulse depends on polarization, intensity of the pump pulse, and delay between the probe pulse and the pump pulse. So this system can be used as an ultrafast all-optical switch which is inspected by the transfer matrix method. After studying the band structure of the one-dimensional photonic crystal, the optical stark effect (OSE was considered on it. Due to the OSE on virtual exciton levels, the switching time can be in the order of picoseconds. Moreover, it is demonstrated that, by introducing errors in width of barrier and well as well as by inserting defect, the reflectivity is reduced. Thus, by employing the mechanism of stark effect MQWs band-gaps can be easily controlled which is useful in designing MWQ based optical switches and filters. By comparing the results, we observe that the reflectivity of MWQ containing 200 periods of InAlAs/InP quantum wells shows the maximum reflectivity of 96%.
Bian, Li-an; Liu, Peiguo; Li, Gaosheng
2016-10-01
For the one-dimensional generalized Fibonacci photonic crystals incorporating graphene, we present many valuable properties and design the tunable devices accordingly with the help of the transfer matrix method in the frequency range of terahertz. For the common structure, all of dielectric layers are cladded by graphene, we design the high-Q tunable filter with double peaks by changing the Fibonacci distribution and chemical potential. In order to reduce the crosstalk of signals through this filter, a heterostructure based on the current structure and the one without graphene is utilized to separate the two peaks. Also, we fabricate the tunable switch by altering the parity of periodic number. Besides, through cladding the graphene on the one of the dielectrics only, we obtain other two kinds of cells. Combining these cells arbitrarily as the supercell to develop the periodic structure, the number of forbidden bands is increased in accordance with certain rules so that this structure with supercell is suitable as the multi-stop filter. If the active medium is introduced, the imaginary part of the complex permittivity of the material would be negative, which means the energy amplification. For our quasi-periodic structures with active medium, the functions of chemical potential, damping constant and reference wavelength are investigated.
Dadoenkova, Yu S; Dadoenkova, N N; Lyubchanskii, I L; Sementsov, D I
2016-05-10
We present a theoretical study of the reshaping of subpicosecond optical pulses in the vicinity of double-peaked defect-mode frequencies in the spectrum of a one-dimensional photonic crystal with two defect layers and calculate the time delay of the transmitted pulses. We used the transfer matrix method for the evaluation of the transmittivity spectra, and the Fourier transform technique for the calculation of the transmitted pulse envelopes. The most considerable reshaping of the pulses takes place for pulses with a carrier frequency in the defect-mode center and with a spectrum wider than the half-width of the defect mode. For pulses with the carrier frequency at the low- and high-frequency peaks of the defect mode, reshaping is strong for the twice as wide pulses. The maximal time delay of a spectrally narrow pulse is of the order of the pulse duration and demonstrates extrema at the frequencies of the defect-mode peaks. The time delay of a wide pulse does not depend on the carrier frequency, but is one order of magnitude larger than the pulse duration.
One-dimensional photonic crystal slot waveguide for silicon-organic hybrid electro-optic modulators.
Yan, Hai; Xu, Xiaochuan; Chung, Chi-Jui; Subbaraman, Harish; Pan, Zeyu; Chakravarty, Swapnajit; Chen, Ray T
2016-12-01
In an on-chip silicon-organic hybrid electro-optic (EO) modulator, the mode overlap with EO materials, in-device effective r33, and propagation loss are among the most critical factors that determine the performance of the modulator. Various waveguide structures have been proposed to optimize these factors, yet there is a lack of comprehensive consideration on all of them. In this Letter, a one-dimensional (1D) photonic crystal (PC) slot waveguide structure is proposed that takes all these factors into consideration. The proposed structure takes advantage of the strong mode confinement within a low-index region in a conventional slot waveguide and the slow-light enhancement from the 1D PC structure. Its simple geometry makes it robust to resist fabrication imperfections and helps reduce the propagation loss. Using it as a phase shifter in a Mach-Zehnder interferometer structure, an integrated silicon-organic hybrid EO modulator was experimentally demonstrated. The observed effective EO coefficient is as high as 490 pm/V. The measured half-wave voltage and length product is less than 1 V·cm and can be further improved. A potential bandwidth of 61 GHz can be achieved and further improved by tailoring the doping profile. The proposed structure offers a competitive novel phase-shifter design, which is simple, highly efficient, and with low optical loss, for on-chip silicon-organic hybrid EO modulators.
Smirnov, A. M.; Golinskaya, A. D.; Ezhova, K.; Kozlova, M.; Stebakova, J. V.; Valchuk, Y. V.
2017-05-01
One-dimensional dynamic photonic crystal was formed by a periodic spatial modulation of dielectric permittivity induced by the two ultrashort laser pulses interference in semiconductor quantum dots CdSe/ZnS (QDs) colloidal solution intersecting at angle θ. The fundamental differences of dynamic photonic crystals from static ones which determine the properties of these transient structures are the following. I. Dynamic photonic crystals lifetimes are determined by the nature of nonlinear changes of dielectric permittivity. II. The refractive index changing is determined by the intensity of the induced standing wave maxima and nonlinear susceptibility of the sample. We use the pump and probe method to create the dynamic one-dimensional photonic crystal and to analyze its features. Two focused laser beams are the pump beams, that form in the colloidal solution of quantum dots dynamic one-dimensional photonic crystal. The picosecond continuum, generated by the first harmonic of laser (1064 nm) passing through a heavy water is used as the probe beam. The self-diffraction of pumping beams on self induced dynamic one-dimensional photonic crystal provides information about spatial combining of laser beams.
DEFF Research Database (Denmark)
Sadrieva, Z. F.; Sinev, I. S.; Samusev, A. K.;
2016-01-01
In this work, we implement CMOS-compatible one-dimensional photonic structure based on silicon-on-insulator wafer supporting optical bound states in the continuum at telecommunication wavelengths — localized optical state with energy lying above the light line of the surrounding space. Such high-......-Q states are very promising for many potential applications ranging from on-chip photonics and optical communications to biological sensing and photovoltaics....
Voronov, Mikhail M
2016-01-01
The approach based on the generalized Kirchhoff's law for calculating photoluminescence spectra of one-dimensional multi-layered structures, in particular, 1D photonic crystals has been developed. It is valid in the local thermodynamic equilibrium approximation and leads to simple and explicit expressions for the photoluminescence intensity. In the framework of the present theory the Purcell factor has been discussed as well.
Photonic band-gap and defect modes of a one-dimensional photonic crystal under localized compression
Sánchez, A.; Porta, A. V.; Orozco, S.
2017-05-01
The rupture of periodicity caused by one defect (defect layer) in a one-dimensional photonic crystal (1DPhC) results in a narrow transmission spectral line in the photonic band-gap, and the field distribution shows a strong confinement in the proximity of the defect layer. In this work, we present a theoretical model to calculate the frequency of defect modes caused by defect layers induced by localized mechanical stress. Two periodical arrangements were studied: one with layers of poly(methyl-methacrylate) (PMMA) and polystyrene (PS), PMMA-PS; the other with layers of PMMA and fused silica (SiO2), PMMA-SiO2. The defect layers were induced by localized compression (tension). The frequencies of the defect modes were calculated using elasto-optical theory and plane wave expansion and perturbation methods. Numerical results show that the frequency of the defect mode increases (decreases) when the compression (tension) increases. Based on the theoretical model developed, we show that compression of n layers of a 1DPhC induces n defect modes whose frequencies depend on the compression magnitude in the case of normal incidence of electromagnetic waves, in accordance with the results reported for other types of defect layers. The methodology shows the feasibility of the plane wave expansion and perturbation methods to study the frequency of the defect modes. Both periodical arrangements are suitable for designing mechanically tunable (1DPhC)-based narrow pass band filters and narrow reflectors in the (60, 65) THz range.
Energy Technology Data Exchange (ETDEWEB)
Askari, Nasim; Eslami, Esmaeil, E-mail: eeslami@iust.ac.ir [Department of Physics, Iran University of Science & Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Mirzaie, Reza [Department of Physics, Shahid Beheshti University, G. C., Evin, Tehran 1983969411 (Iran, Islamic Republic of)
2015-11-15
The photonic band gap of obliquely incident terahertz electromagnetic waves in a one-dimensional plasma photonic crystal is studied. The periodic structure consists of lossless dielectric and inhomogeneous plasma with a parabolic density profile. The dispersion relation and the THz wave transmittance are analyzed based on the electromagnetic equations and transfer matrix method. The dependence of effective plasma frequency and photonic band gap characteristics on dielectric and plasma thickness, plasma density, and incident angle are discussed in detail. A theoretical calculation for effective plasma frequency is presented and compared with numerical results. Results of these two methods are in good agreement.
Sol-gel fabrication of one-dimensional photonic crystals with predicted transmission spectra
Ilinykh, V. A.; Matyushkin, L. B.
2016-08-01
One-dimensional multilayer structures of periodically alternating low refractive index (silica) and high refractive index (titania) materials have been deposited by sol-gel spincoating. Experimental spectra of the structures are in agreement with spectra calculated by transfer matrix technique. As an example, theoretical and experimental spectra with a stop band corresponding 600 nm-reflection are shown.
Barillaro, Giuseppe
2015-01-01
In this work, all-silicon, integrated optofluidic platforms, fabricated by electrochemical micromachining technology, making use of vertical, one-dimensional high-aspect- ratio photonic crystals for flow-through (bio)sensing applications are reviewed. The potential of such platforms for point-of-care applications is discussed for both pressure-driven and capillarity- driven operations with reference to refractometry and biochemical sensing.
Tyc, Michał H.; Salejda, Włodzimierz; Klauzer-Kruszyna, Agnieszka; Tarnowski, Karol
2007-05-01
The dispersion relation for polarized light transmitting through a one-dimensional superlattice composed of aperiodically arranged layers made of ordinary dielectric and negative refraction metamaterials is calculated with finite element method. Generalized Fibonacci, generalized Thue-Morse, double-periodic and Rudin-Shapiro superlattices are investigated, using their periodic approximants. Strong dispersion of metamaterials is taken into account. Group velocities and effective refraction indices in the structures are calculated. The self-similar structure of the transmission spectra is observed.
Institute of Scientific and Technical Information of China (English)
Xia Li; Kang Xie; Haiming Jiang
2008-01-01
The transmission properties of one-dimensional photonic crystals containing double-negative and singlenegative materials are studied theoretically.A special kind of photonic band gap is found in this structure.This gap is invariant with scaling and insensitive to thickness fluctuation.But when changing the ratio of the thickness of two media.the width of the gap could be enlarged.The defect modes are analyzed by inducing a linear defect layer in the structure.It is found that the number of defect modes will increase when the thickness of the defect layer becomes larger.
DEFF Research Database (Denmark)
Nysteen, Anders; Kristensen, Philip Trøst; McCutcheon, Dara
2015-01-01
We develop a wavefunction approach to describe the scattering of two photons on a quantum emitter embedded in a one-dimensional waveguide. Our method allows us to calculate the exact dynamics of the complete system at all times, as well as the transmission properties of the emitter. We show...... that the nonlinearity of the emitter with respect to incoming photons depends strongly on the emitter excitation and the spectral shape of the incoming pulses, resulting in transmission of the photons which depends crucially on their separation and width. In addition, for counter-propagating pulses, we analyze...... the induced level of quantum correlations in the scattered state, and we show that the emitter behaves as a nonlinear beam-splitter when the spectral width of the photon pulses is similar to the emitter decay rate....
Local phase measurements of light in a one-dimensional photonic crystal
Flück, E.; Otter, A.M.; Korterik, J.P.; Balistreri, M.L.M.; Kuipers, L.; Hulst, van N.F.
2001-01-01
For the first time the local optical phase evolution in and around a small, one-dimensional photonic crystal has been visualized with a heterodyne interferometric photon scanning tunnelling microscope. The measurements show an exponential decay of the optical intensity inside the crystal, which con
Reflectance properties of one-dimensional metal-dielectric ternary photonic crystal
Energy Technology Data Exchange (ETDEWEB)
Pandey, G. N., E-mail: gnpandey2009@gmail.com [Department of Physics, Amity Institute of Applied Sciences, AmityUniversity, Noida (U.P.) (India); Kumar, Narendra [Department of Physics (CASH), Modi University of Science and Technology, Lakshmangarh, Sikar, Rajsthan (India); Thapa, Khem B. [Department of Physics, U I E T, ChhatrapatiShahu Ji Maharaj University, Kanpur- (UP) (India); Ojha, S. P. [Department of Physics IIT, Banaras Hindu University (India)
2016-05-06
Metallic photonic crystal has a very important application in absorption enhancement in solar cells. It has been found that an ultra-thin metallic layer becomes transparent due to internal scattering of light through the each interface of the dielectric and metal surfaces. The metal has absorption due to their surface plasmon and the plasmon has important parameters for changing optical properties of the metal. We consider ternary metallic-dielectric photonic crystal (MDPC) for having large probabilities to change the optical properties of the MDPC and the photonic crystals may be changed by changing dimensionality, symmetry, lattice parameters, Filling fraction and effective refractive index refractive index contrast. In this present communication, we try to show that the photonic band gap in ternary metal-dielectric photonic crystal can be significantly enlarged when air dielectric constant is considered. All the theoretical analyses are made based on the transfer matrix method together with the Drude model of metal.
Reflectance properties of one-dimensional metal-dielectric ternary photonic crystal
Pandey, G. N.; Kumar, Narendra; Thapa, Khem B.; Ojha, S. P.
2016-05-01
Metallic photonic crystal has a very important application in absorption enhancement in solar cells. It has been found that an ultra-thin metallic layer becomes transparent due to internal scattering of light through the each interface of the dielectric and metal surfaces. The metal has absorption due to their surface plasmon and the plasmon has important parameters for changing optical properties of the metal. We consider ternary metallic-dielectric photonic crystal (MDPC) for having large probabilities to change the optical properties of the MDPC and the photonic crystals may be changed by changing dimensionality, symmetry, lattice parameters, Filling fraction and effective refractive index refractive index contrast. In this present communication, we try to show that the photonic band gap in ternary metal-dielectric photonic crystal can be significantly enlarged when air dielectric constant is considered. All the theoretical analyses are made based on the transfer matrix method together with the Drude model of metal.
Directory of Open Access Journals (Sweden)
M Sharifi
2016-09-01
Full Text Available In recent years, development of highly sensitive biosensors is the main purpose of researchers to diagnose and prevent diseases. Accordingly, in this paper, surface plasmon resonance (SPR biosensor has been designed based on one dimensional layered structures. With regard to the fact that the quality of SPR sensors strongly depends on the reflectance amplitude and full width at half maximum (FWHM of the SPR curves, a novel structure, , is presented using transfer matrix method (TMM, to satisfy these two condition. Besides, the sensitivity of this biosensor has been calculated and it has been employed to diagnose leukemia for Jurkat cells.
Viscor, Daniel; Lesanovsky, Igor
2014-01-01
We investigate the propagation of a single photon under conditions of electromagnetically induced transparency in two parallel one-dimensional atomic clouds which are coupled via Rydberg dipole-dipole interaction. Initially the system is prepared with a single delocalized Rydberg excitation shared between the two ensembles and the photon enters both of them in an arbitrary path-superposition state. By properly aligning the transition dipoles of the atoms of each cloud we show that the photon can be partially transferred from one cloud to the other via the dipole-dipole interaction. This coupling leads to the formation of dark and bright superpositions of the light which experience different absorption and dispersion. We show that this feature can be exploited to filter the incident photon in such a way that only a desired path-superposition state is transmitted transparently. Finally, we generalize the analysis to the case of N coupled one-dimensional clouds. We show that within some approximations the dynami...
A leap over Dirac cones in one-dimensional graphene-based photonic crystal
Energy Technology Data Exchange (ETDEWEB)
Jahani, D., E-mail: dariush110@gmail.com [Young Researchers and Elite Club, Kermanshah branch, Islamic Azad University, Kermanshah (Iran, Islamic Republic of); Abaspour, L.; Soltani-Vala, A.; Barvestani, J. [Department of Solid State Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of)
2016-06-15
The existence of a photonic bandgap in the visible range of light spectrum corresponding to a 1D graphene-based photonic crystal which recently has been proposed and is formed by embedding alternatively graphene layers into a dielectric background is investigated in this paper. By the use of the complete form of optical conductivity for the full expression of the tight-binding Hamiltonian of graphene layer, we numerically demonstrate an appeared bandgap in the visible region of the spectrum which can open up new route for further high-frequency applications of graphene-based photonic devices. It is revealed that the associated bandgap could be altered by changing the hopping energy and the amount of chemical potential leading to broadening the forbidden frequency regions with further increasing. Finally, it is also shown that the tunability feature of the photonic bandgap could be affected by changing the hopping energy.
Energy Technology Data Exchange (ETDEWEB)
Song, Guo-Zhu; Zhang, Mei; Ai, Qing; Yang, Guo-Jian [Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875 (China); Alsaedi, Ahmed; Hobiny, Aatef [NAAM-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Deng, Fu-Guo, E-mail: fgdeng@bnu.edu.cn [Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875 (China); NAAM-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)
2017-03-15
We propose a heralded quantum repeater based on the scattering of photons off single emitters in one-dimensional waveguides. We show the details by implementing nonlocal entanglement generation, entanglement swapping, and entanglement purification modules with atoms in waveguides, and discuss the feasibility of the repeater with currently achievable technology. In our scheme, the faulty events can be discarded by detecting the polarization of the photons. That is, our protocols are accomplished with a fidelity of 100% in principle, which is advantageous for implementing realistic long-distance quantum communication. Moreover, additional atomic qubits are not required, but only a single-photon medium. Our scheme is scalable and attractive since it can be realized in solid-state quantum systems. With the great progress on controlling atom-waveguide systems, the repeater may be very useful in quantum information processing in the future.
Institute of Scientific and Technical Information of China (English)
Guo Ji-Yong; Chen Hong; Li Hong-Qiang; Zhang Ye-Wen
2008-01-01
We take a finite dielectric photonic crystal as a homogeneous slab and have extracted the effective parameters. Our systematic study shows that the effective permittivity or permeability of dielectric photonic crystal is negative within a band gap region. This means that the band gap might act as ε-negative materials (ENMs) with ε0, or μ-negative materials (MNMs) with ε>0 and μ<0. Moreover the effective parameters sensitively rely on size, surface termination, symmetry, etc. The effective parameters can be used to design full transmission tunnelling modes and amplify evanescent wave. Several cases are studied and the results show that dielectric photonic band gap can indeed mimic a single negative material (ENM or MNM) under some restrictions.
Nonlinear frequency conversion effect in a one-dimensional graphene-based photonic crystal
Wicharn, S.; Buranasiri, P.
2015-07-01
In this research, the nonlinear frequency conversion effect based on four-wave mixing (FWM) principle in a onedimensional graphene-based photonics crystal (1D-GPC) has been investigated numerically. The 1D-GPC structure is composed of two periodically alternating material layers, which are graphene-silicon dioxide bilayer system and silicon membrane. Since, the third-order nonlinear susceptibility χ(3) of bilayer system is hundred time higher than pure silicon dioxide layer, so the enhancement of FWM response can be achieved inside the structure with optimizing photon energy being much higher than a chemical potential level (μ) of graphene sheet. In addition, the conversion efficiencies of 1DGPC structure are compared with chalcogenide based photonic structure for showing that 1D-GPC structure can enhance nonlinear effect by a factor of 100 above the chalcogenide based structure with the same structure length.
Sodagar, Majid; Eftekhar, Ali A; Adibi, Ali
2014-01-01
Optical bistability provides a simple way to control light with light. We demonstrate low-power thermo-optical bistability caused by the Joule heating mechanism in a one-dimensional photonic crystal (PC) nanobeam resonator with a moderate quality factor (Q ~ 8900) with an embedded reverse-biased pn-junction. We show that the photocurrent induced by the linear absorption in this compact resonator considerably reduces the threshold optical power. The proposed approach substantially relaxes the requirements on the input optical power for achieving optical bistability and provides a reliable way to stabilize the bistable features of the device.
Institute of Scientific and Technical Information of China (English)
SANG Hong-Yi; LI Zhi-Yuan; GU Ben-Yuan
2005-01-01
@@ Defect modes in one-dimensional photonic crystals (PCs) can be readily detected from the solution of the transmission spectra via the standard transfer-matrix method. We adopt an analytic Bloch-mode approach to examine this problem in terms of eigenmode solutions and investigate the dispersion behaviour of localized defect modes supported by a defect layer sandwiched within two symmetric semi-infinite PCs that are made from multiple constituents. The results show that the number of defect modes grows when the dielectric constant and width of the defect layer increase.
Timofeev, Ivan V; Gunyakov, Vladimir A; Myslivets, Sergey A; Arkhipkin, Vasily G; Vetrov, Stepan Ya; Lee, Wei; Zyryanov, Victor Ya
2011-01-01
Defect modes are investigated in a band gap of an electrically tunable one-dimensional photonic crystal infiltrated with a twisted-nematic liquid crystal (1D PC/TN). Their frequency shift and interference under applied voltage are studied both experimentally and theoretically. We deal with the case where the defect layer thickness is much larger than the wavelength (Mauguin condition). It is shown theoretically that the defect modes could have a complex structure with the elliptic polarization. Two series of polarized modes interact with each other and exhibit an avoided crossing phenomenon in the case of opposite parity.
Sodagar, Majid; Miri, Mehdi; Eftekhar, Ali A; Adibi, Ali
2015-02-01
Optical bistability provides a simple way to control light with light. We demonstrate low-power thermo-optical bistability caused by the Joule heating mechanism in a one-dimensional photonic crystal (PC) nanobeam resonator with a moderate quality factor (Q ~8900) with an embedded reverse-biased pn-junction. We show that the photocurrent induced by the linear absorption in this compact resonator considerably reduces the threshold optical power. The proposed approach substantially relaxes the requirements on the input optical power for achieving optical bistability and provides a reliable way to stabilize the bistable features of the device.
Energy Technology Data Exchange (ETDEWEB)
Zhang Haifeng [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Liu Shaobin [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); State Key Laboratory of Millimeter Waves of Southeast University, Nanjing Jiangsu 210096 (China); Kong Xiangkun; Bian Borui; Dai Yi [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)
2012-11-15
In this paper, an omnidirectional photonic band gap realized by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure, which is composed of homogeneous unmagnetized plasma and two kinds of isotropic dielectric, is theoretically studied by the transfer matrix method. It has been shown that such an omnidirectional photonic band gap originates from Bragg gap in contrast to zero-n gap or single negative (negative permittivity or negative permeability) gap, and it is insensitive to the incidence angle and the polarization of electromagnetic wave. From the numerical results, the frequency range and central frequency of omnidirectional photonic band gap can be tuned by the thickness and density of the plasma but cease to change with increasing Fibonacci order. The bandwidth of omnidirectional photonic band gap can be notably enlarged. Moreover, the plasma collision frequency has no effect on the bandwidth of omnidirectional photonic band gap. It is shown that such new structure Fibonacci quasiperiodic one-dimensional ternary plasma photonic crystals have a superior feature in the enhancement of frequency range of omnidirectional photonic band gap compared with the conventional ternary and conventional Fibonacci quasiperiodic ternary plasma photonic crystals.
Feng, Xi; Li, Hu; Yuxia, Tang
2016-07-01
Under total reflection conditions, it typically seems as though light waves will be reflected completely on the interface; in actuality, the waves can penetrate the medium as evanescent waves. In this paper, we present a twinned lattice photonic crystal with a unit cell composed of AB layers and their mirror. We assume that the refractive index n 0 of the input and output end is equal to n B and larger than n A . We first demonstrate the dependence of band structure on the incidence angle and normalized wavelength, in which the resonant tunneling bands are exposed. We then draw a comparison of bands between ABBA and AB. To conclude, we discuss the resonant tunneling effect in the twinned lattice photonic crystal under the total reflection conditions. As incidence angle increases, the resonant tunneling band ultimately vanishes completely.
Directory of Open Access Journals (Sweden)
Maria Alvaro
2013-02-01
Full Text Available A one-dimensional photonic crystal (1DPC based on a planar stack of dielectric layers is used as an optical transducer for biosensing, upon the coupling of TE-polarized Bloch Surface Waves (BSW. The structure is tailored with a polymeric layer providing a chemical functionality facilitating the covalent binding of orienting proteins needed for a subsequent grafting of antibodies in an immunoassay detection scheme. The polymeric layer is impregnated with Cy3 dye, in such a way that the photonic structure can exhibit an emissive behavior. The BSW-coupled fluorescence shift is used as a means for detecting refractive index variations occurring at the 1DPC surface, according to a label-free concept. The proposed working principle is successfully demonstrated in real-time tracking of protein G covalent binding on the 1DPC surface within a fluidic cell.
Frascella, Francesca; Ricciardi, Serena; Rivolo, Paola; Moi, Valeria; Giorgis, Fabrizio; Descrovi, Emiliano; Michelotti, Francesco; Munzert, Peter; Danz, Norbert; Napione, Lucia; Alvaro, Maria; Bussolino, Federico
2013-02-05
A one-dimensional photonic crystal (1DPC) based on a planar stack of dielectric layers is used as an optical transducer for biosensing, upon the coupling of TE-polarized Bloch Surface Waves (BSW). The structure is tailored with a polymeric layer providing a chemical functionality facilitating the covalent binding of orienting proteins needed for a subsequent grafting of antibodies in an immunoassay detection scheme. The polymeric layer is impregnated with Cy3 dye, in such a way that the photonic structure can exhibit an emissive behavior. The BSW-coupled fluorescence shift is used as a means for detecting refractive index variations occurring at the 1DPC surface, according to a label-free concept. The proposed working principle is successfully demonstrated in real-time tracking of protein G covalent binding on the 1DPC surface within a fluidic cell.
One-Dimensional Dielectric/Metallic Hybrid Materials for Photonic Applications.
Li, Yong Jun; Xiong, Xiao; Zou, Chang-Ling; Ren, Xi Feng; Zhao, Yong Sheng
2015-08-01
Explorations of 1D nanostructures have led to great progress in the area of nanophotonics in the past decades. Based on either dielectric or metallic materials, a variety of 1D photonic devices have been developed, such as nanolasers, waveguides, optical switches, and routers. What's interesting is that these dielectric systems enjoy low propagation losses and usually possess active optical performance, but they have a diffraction-limited field confinement. Alternatively, metallic systems can guide light on deep subwavelength scales, but they suffer from high metallic absorption and can work as passive devices only. Thus, the idea to construct a hybrid system that combines the merits of both dielectric and metallic materials was proposed. To date, unprecedented optical properties have been achieved in various 1D hybrid systems, which manifest great potential for functional nanophotonic devices. Here, the focus is on recent advances in 1D dielectric/metallic hybrid systems, with a special emphasis on novel structure design, rational fabrication techniques, unique performance, as well as their wide application in photonic components. Gaining a better understanding of hybrid systems would benefit the design of nanophotonic components aimed at optical information processing.
Defect modes of one-dimensional photonic-crystal structure with a resonance nanocomposite layer
Moiseev, S. G.; Ostatochnikov, V. A.
2016-08-01
We have studied the defect modes of a structure of Fabry - Perot interferometer type, in which the layer separating Bragg mirrors is made of a heterogeneous composite material with metallic nanoscale inclusions. Effective optical characteristics of the nanocomposite material have resonance singularities in the visible region of the spectrum, which are conditioned by the surface plasmon resonance of metallic nanoparticles. It is shown that the spectral profile of the energy bandgap of the photonic structure can be modified by varying the volume fraction and size of nanoparticles. The interrelation of splitting and shift of defect modes with structural parameters of a nanocomposite layer is studied by means of a numerical - graphical method with allowance for the frequency dependences of phases and amplitudes of reflectances in Bragg mirrors.
Periodic transmission peaks in non-periodic disordered one-dimensional photonic structures
Kriegel, Ilka
2015-01-01
A better understanding of the optical properties of a device structure characterized by a random arrangement of materials with different dielectric properties at a length scale comparable to the wavelength of light is crucial for the realization of new optical and optoelectronic devices. Here we have studied the light transmission of disordered photonic structures made with two and three different materials, characterized by the same optical thickness. In their transmission spectra a formation of peaks, with a transmission of up to 75%, is evident. The spectral position of such peaks is very regular, which is a result of the constraint that all layers have the same optical thickness. This gives rise to a manifold of applications such as new types of bandpass filters and resonators for distributed feedback lasers.
Kim, Dong Wook; Kim, Seung Hwan; Lee, Seoung Hun; Jong, Heung Sun; Lee, Jong-Moo; Lee, El-Hang; Kim, Kyong Hon
2013-12-02
Enhanced four-wave-mixing (FWM) effects have been observed with the help of large group-indices near the band edges in one-dimensional (1-D) silicon photonic crystal waveguides (Si PhCWs). A significant increase of the FWM conversion efficiency of about 17 dB was measured near the transmission band edge of the 1-D PhCW through an approximate 3.2 times increase of the group index from 8 to 24 with respect to the central transmission band region despite a large group-velocity dispersion. Numerical analyses based on the coupled-mode equations for the degenerated FWM process describe the experimentally measured results well. Our results indicate that the 1-D PhCWs are good candidates for large group-index enhanced nonlinearity devices even without having any special dispersion engineering.
Institute of Scientific and Technical Information of China (English)
Liu Jiang-Tao; Zhou Yun-Song; Wang Fu-He; Gu Ben-Yuan
2005-01-01
We present a new type of optical filter with an ultra-narrow bandwidth and a wide field-of-view (FOV). This kind of optical filter consists of one-dimensional photonic crystal (PC) incorporating an anomalous-dispersion-material (ADM) with, for instance, an anomalous dispersion of 6P3/2 ← 6S1/2 hyperfine structure transition of a caesium atom.The transmission spectra of optical filters are calculated by using the transfer-matrix method. The simulation results show that the designed optical filter has a bandwidth narrower than 0.33GHz and a wide FOV of ±30° as well. The response of transmission spectrum to an external magnetic field is also investigated.
Institute of Scientific and Technical Information of China (English)
ZHENG Gai-Ge; XIAN Feng-Lin; LI Xiang-Yin
2011-01-01
We design an effective light trapping scheme through engineering metallic gratings and one-dimensional dielectric photonic crystals (PhCs) to increase the optical path length of light within the solar cells. This incorporation can result in broadband optical absorption enhancement not only for transverse magnetic polarized light but also for transverse-electric polarization. Even when no plasmonic mode can be excited, due to the high reflection of the PhCs, the absorption in the active region can still be enhanced. Rigorous coupled wave analysis results demonstrate that such a hybrid structure boosts the overall cell performance by increasing the light trapping capabilities and is especially effective at the silicon band edge. This kind of design can be used to increase the optical absorption over a wide spectral range and is relatively independent of the angle of incidence.%@@ We design an effective light trapping scheme through engineering metallic gratings and one-dimensional dielectric photonic crystals(PhCs) to increase the optical path length of light within the solar cells.This incorporation can result in broadband optical absorption enhancement not only for transverse magnetic polarized light but also for transverse-electric polarization.Even when no plasmonic mode can be excited,due to the high reflection of the PhCs,the absorption in the active region can still be enhanced.Rigorous coupled wave analysis results demonstrate that such a hybrid structure boosts the overall cell performance by increasing the light trapping capabilities and is especially effective at the silicon band edge.This kind of design can be used to increase the optical absorption over a wide spectral range and is relatively independent of the angle of incidence.
Shukla, Shikha; Prasad, Surendra; Singh, Vivek
2016-09-01
We have studied the properties of surface modes on one dimensional magnetized plasma photonic crystals in two configurations: Faraday and Voigt configurations. The results have been demonstrated by using the transfer matrix method and employing boundary conditions for TE and TM modes, respectively. For the Voigt effect, only the TM mode is considered because the TE modes under the influence of external magnetic field have the same properties as un-magnetized plasma. The influence of external magnetic field has been studied for three cases, i.e., TE left circular polarization, TE right circular polarization, and TM surface modes. It is shown that the properties of surface modes can be tuned correspondingly by changing the cap layer thickness, wave vector, and external magnetic field in the desired photonic band gap. The results show that collision frequency has a negligible effect on surface modes. A new type of wave called Fano mode has been reported for the Voigt effect for the TM mode in the first band gap. Proof of its existence has been demonstrated in the present paper.
Efficient three-photon excitation of quasi-one-dimensional strontium Rydberg atoms with n ˜300
Ye, S.; Zhang, X.; Dunning, F. B.; Yoshida, S.; Hiller, M.; Burgdörfer, J.
2014-07-01
The efficient production of very-high-n, n ˜300, quasi-one-dimensional (quasi-1D) strontium Rydberg atoms through three-photon excitation of extreme Stark states in the presence of a weak dc field is demonstrated using a crossed laser-atom beam geometry. Strongly polarized quasi-1D states with large permanent dipole moments ˜1.2n2 a.u. can be created in the beam at densities (˜106 cm-3) where dipole blockade effects should become important. A further advantage of three-photon excitation is that the product F states are sensitive to the presence of external fields, allowing stray fields to be reduced to very small values. The experimental data are analyzed using quantum calculations based on a two-active-electron model together with classical trajectory Monte Carlo simulations. These allow determination of the atomic dipole moments and confirm that stray fields can be reduced to ≤25μV cm-1.
Sagawa, Misuzu; Goto, Shigeo; Hosomi, Kazuhiko; Sugawara, Toshiki; Katsuyama, Toshio; Arakawa, Yasuhiko
2008-08-01
Utilizing large optical group-velocity dependence on wavelength without polarization-mode dependence, we have developed an ultracompact dispersion compensator based on multiple one-dimensional coupled-defect-type photonic crystals. The photonic crystal of the compensator, designed for a 1.55-µm optical communication system, consists of a multilayer thin-film structure and defect layers. The thin-film structure is substrate-free, which enables the compensator to be small, that is, a 1.4-mm-edge cube. To obtain a large group-velocity difference, 60 substrate-free films were stacked to form the compensator. The passband of the compensator is 2 nm, and the group-delay time difference within the band is more than 100 ps. A dispersion-compensator module integrated with a photodetector was fabricated. A 40-Gbit/s non-return-to-zero optical-transmission experiment was carried out with the compensator, demonstrating dispersion-compensation operation over a 10-km standard single-mode fiber, the dispersion of which corresponds to 170 ps/nm.
Institute of Scientific and Technical Information of China (English)
MIAO Feng-Juan; ZHANG Jie; XU Shao-Hui; WANG Lian-Wei; CHU Jun-Hao; CAO Zhi-Shen; ZHAN Peng; WANG Zhen-Lin
2009-01-01
@@ With the aid of photolithography, an array of one-dimensional porous silicon photonic crystal reflector islands for a far infrared image detector ranging from 10μm to 14μm is successfully fabricated. Silicon nitride formed by low pressure chemical vapor deposition (LPCVD) was used as the masking layer for the island array formation. After etching, the microstructures were examined by a scanning electron microscope and the optical properties were studied by Fourier transform infrared spectroscopy, the result indicates that the multilayer structure could be obtained in the perpendicular direction via periodically alternative etching current in each pre-patteru. At the same time, the island array has a well-proportioned lateral etching effect, which is very useful for the thermal isolation in lateral orientation of the application in devices. It is concluded that regardless of the absorption of the deposition layer on the substrate, the localized photonic crystalline islands have higher reflectivity. The designed islands structure not only prevents the cracking of the porous silicon layers but is also useful for the application in the cold part for the sensor devices and the interconnection of each pixel.
Jamshidi-Ghaleh, Kazem; Ebrahimpour, Zeinab; Moslemi, Fatemeh
2015-07-01
The transmission spectrum properties of the one-dimensional ternary photonic crystal (1DTPC) structure, composed of dielectric (D), metal (M) and gain (G) materials, with three different arrangements of (DGM)N, (GDM)N and (DMG)N, where N is the number of periodicity, were investigated. Two full photonic band gaps and N-1 resonant peaks, localized between them, were observed on transmittance spectra on near-UV spectrum region. When the gained layer was placed in front of the metal, the peaks appeared with higher resolution. There is a peak, localized on the higher band-edge of the first gap, which shows very interesting property than the other peaks. Thus, it amplifies and compresses faster with increase in the N and strength of the gain coefficient. The effects of the gain coefficient and periodicity number are graphically illustrated. This communication presents a PC structure that can be a good candidate to design an amplifying and compressing single or multi-channel optical filter in the UV region.
Energy Technology Data Exchange (ETDEWEB)
Jena, S., E-mail: shuvendujena9@gmail.com [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Tokas, R.B.; Sarkar, P. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Misal, J.S.; Maidul Haque, S.; Rao, K.D. [Photonics & Nanotechnology Section, BARC-Vizag, Autonagar, Atomic & Molecular Physics Division, Bhabha Atomic Research Centre facility, Visakhapatnam 530 012 (India); Thakur, S.; Sahoo, N.K. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2016-01-29
One dimensional photonic crystal (1DPC) of TiO{sub 2}/SiO{sub 2} multilayer has been fabricated by sequential asymmetric bipolar pulsed dc magnetron sputtering of TiO{sub 2} and radio frequency magnetron sputtering of SiO{sub 2} to achieve wide omnidirectional photonic band in the visible region. The microstructure and optical response of the TiO{sub 2}/SiO{sub 2} photonic crystal have been characterized by atomic force microscopy, scanning electron microscopy and spectrophotometry respectively. The surface of the photonic crystal is very smooth having surface roughness of 2.6 nm. Reflection and transmission spectra have been measured in the wavelength range 300 to 1000 nm for both transverse electric and transverse magnetic waves. Wide high reflection photonic band gap (∆ λ = 245 nm) in the visible and near infrared regions (592–837 nm) at normal incidence has been achieved. The measured photonic band gap (PBG) is found well matching with the calculated photonic band gap of an infinite 1DPC. The experimentally observed omnidirectional photonic band 592–668 nm (∆ λ = 76 nm) in the visible region with band to mid-band ratio ∆ λ/λ = 12% for reflectivity R > 99% over the incident angle range of 0°–70° is found almost matching with the calculated omnidirectional PBG. The omnidirectional reflection band is found much wider as compared to the values reported in literature so far in the visible region for TiO{sub 2}/SiO{sub 2} periodic photonic crystal. - Highlights: • TiO{sub 2}/SiO{sub 2} 1DPC has been fabricated using magnetron sputtering technique. • Experimental optical response is found good agreement with simulation results. • Wide omnidirectional photonic band in the visible spectrum has been achieved.
Fleming, L.; Gibson, D.; Song, S.; Hutson, D.; Reid, S.; MacGregor, C.; Clark, C.
2017-02-01
Mid-IR carbon dioxide (CO2) gas sensing is critical for monitoring in respiratory care, and is finding increasing importance in surgical anaesthetics where nitrous oxide (N2O) induced cross-talk is a major obstacle to accurate CO2 monitoring. In this work, a novel, solid state mid-IR photonics based CO2 gas sensor is described, and the role that 1- dimensional photonic crystals, often referred to as multilayer thin film optical coatings [1], play in boosting the sensor's capability of gas discrimination is discussed. Filter performance in isolating CO2 IR absorption is tested on an optical filter test bed and a theoretical gas sensor model is developed, with the inclusion of a modelled multilayer optical filter to analyse the efficacy of optical filtering on eliminating N2O induced cross-talk for this particular gas sensor architecture. Future possible in-house optical filter fabrication techniques are discussed. As the actual gas sensor configuration is small, it would be challenging to manufacture a filter of the correct size; dismantling the sensor and mounting a new filter for different optical coating designs each time would prove to be laborious. For this reason, an optical filter testbed set-up is described and, using a commercial optical filter, it is demonstrated that cross-talk can be considerably reduced; cross-talk is minimal even for very high concentrations of N2O, which are unlikely to be encountered in exhaled surgical anaesthetic patient breath profiles. A completely new and versatile system for breath emulation is described and the capability it has for producing realistic human exhaled CO2 vs. time waveforms is shown. The cross-talk inducing effect that N2O has on realistic emulated CO2 vs. time waveforms as measured using the NDIR gas sensing technique is demonstrated and the effect that optical filtering will have on said cross-talk is discussed.
Ultra-wide tuning single channel filter based on one-dimensional photonic crystal with an air cavity
Zhao, Xiaodan; Yang, Yibiao; Chen, Zhihui; Wang, Yuncai; Fei, Hongming; Deng, Xiao
2017-02-01
By inserting an air cavity into a one-dimensional photonic crystal of LiF/GaSb, a tunable filter covering the whole visible range is proposed. Following consideration of the dispersion of the materials, through modulating the thickness of the air cavity, we demonstrate that a single resonant peak can shift from 416.1 to 667.3 nm in the band gap at normal incidence by means of the transfer matrix method. The research also shows that the transmittance of the channel can be maximized when the number of periodic LiF/GaSb layers on one side of the air defect layer is equal to that of the other side. When adding a period to both sides respectively, the full width at half maximum of the defect mode is reduced by one order of magnitude. This structure will provide a promising approach to fabricate practical tunable filters in the visible region with ultra-wide tuning range. Project supported by the National Natural Science Foundation of China (Nos. 61575138, 61307069, 51205273), and the Top Young Academic Leaders and the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi.
Zhang, Ji-Kui; Shi, Jia-Ming; Zhao, Da-Peng; Chen, Yu-Zheng
2017-07-01
To restrain the infrared radiation from high temperature objects to decrease the probability of being discovered by infrared detectors operating in the mid- and far-infrared atmospheric windows, we design a one-dimensional heterostructure photonic crystal (PC) using low-cost coating materials Te and ZnSe, and test its reflection spectra and radiant temperature. The tested results show that this PC has high average reflectance in 3- to 5-μm and 8- to 14-μm wavebands, which is 86.72% and 72.91%, respectively, and the corresponding emissivity is 0.072 and 0.194, respectively. The radiant temperatures of the PC are always lower than those of the background, with the maximal difference of the radiant temperature being 31.97°C corresponding to a background radiant temperature of 75.64°C. The study confirms that the deposited PC can effectively decrease the infrared radiation in mid- and far-infrared bands.
Saleki, Ziba; Entezar, Samad Roshan; Madani, Amir
2017-01-10
The transmission properties of a one-dimensional defective photonic crystal have been investigated using the transfer matrix method. A layer of graphene-based hyperbolic metamaterial whose optical axis is tilted with respect to the interface is taken as a defect. It is shown that two kinds of the defect modes can be found in the band gaps of the structure for TM-polarized waves. One kind is created at the frequency range in which the principle elements of the effective permittivity tensor of the defect layer have the same signs. The frequency of this kind of defect mode is independent from the orientation of the optical axis of the defect layer. The other one is created at the hyperbolic dispersion frequency range. Such a defect mode appears due to the anisotropic behavior of the defect layer and its frequency strongly depends on the orientation of the optical axis. Unlike the conventional defect modes, the magnetic field of this defect mode is localized around the defect layer.
Amri, R.; Sahel, S.; Gamra, D.; Lejeune, M.; Clin, M.; Zellama, K.; Bouchriha, H.
2017-04-01
One dimensional photonic crystal based on a mixture of an organic compound HMDSO and nitrogen N2, is elaborated by radiofrequency Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) at different radiofrequency powers. The variation of the radiofrequency power for a flow of N2/HMDSO ratio equal to 0.4, leads to obtain two kinds of layers A and B with refractive index nA = 2 and nB = 1.55 corresponding to RF power of 200 W and 20 W, respectively. The analysis of the infrared results shows that these layers have the same chemical composition element with different structure. These layers, which exhibit a good indexes difference (nA - nB) contrast, allowed then the elaboration of a one-photonic crystal from the same initial gas mixture, which is the aim of this work. After the optimization of the layers thickness, we have measured transmission and reflection spectra and we found that the photonic band gap (PBG) appears after 15 periods of alternating A and B deposited layers. The introduction of defect in the structure leads to obtain a localized mode in the center of the PBG corresponding to the telecommunication wave length 1.55 μm. Finally, we have successfully interpreted our experimental results by using a theoretical model based on transfer matrix method.
Olkhovsky, V. S.
2014-05-01
The formal mathematical analogy between time-dependent quantum equation for the nonrelativistic particles and time-dependent equation for the propagation of electromagnetic waves had been studied in [A. I. Akhiezer and V. B. Berestezki, Quantum Electrodynamics (FM, Moscow, 1959) [in Russian] and S. Schweber, An Introduction to Relativistic Quantum Field Theory, Chap. 5.3 (Row, Peterson & Co, Ill, 1961)]. Here, we deal with the time-dependent Schrödinger equation for nonrelativistic particles and with time-dependent Helmholtz equation for electromagnetic waves. Then, using this similarity, the tunneling and multiple internal reflections in one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) particle and photon tunneling are studied. Finally, some conclusions and future perspectives for further investigations are presented.
Institute of Scientific and Technical Information of China (English)
CHENG Mu-Tian; SONG Yan-Yan; LUO Ya-Qin; ZHAO Guang-xing
2011-01-01
We investigate theoretically the single-photon scattering by a A-type three-level system interacting with a whispering-gallery-type resonator which is coupled to a one-dimensional waveguide by full quantum-mechanical approach,The single-photon transmission amplitude and reflection amplitude are obtained exactly via real-space approach. The single-photon transport properties controlling by classic optical field are discussed. The critical coupling condition in the coupled waveguide-whispering-gallery resonator-atom with three-level system is also analyzed.
Wang, Yuwen; Zhang, Yongyou; Zhang, Qingyun; Zou, Bingsuo; Schwingenschlogl, Udo
2016-01-01
We study the dynamics of an ultrafast single photon pulse in a one-dimensional waveguide two-point coupled with a Jaynes-Cummings system. We find that for any single photon input the transmissivity depends periodically on the separation between the two coupling points. For a pulse containing many plane wave components it is almost impossible to suppress transmission, especially when the width of the pulse is less than 20 times the period. In contrast to plane wave input, the waveform of the pulse can be modified by controlling the coupling between the waveguide and Jaynes-Cummings system. Tailoring of the waveform is important for single photon manipulation in quantum informatics. PMID:27653770
Energy Technology Data Exchange (ETDEWEB)
Vetrov, S Ya; Timofeev, I V [L.V.Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Academgorodok, Krasnoyarsk (Russian Federation); Pankin, P S [Siberian Federal University, Krasnoyarsk (Russian Federation)
2014-09-30
We have studied the spectral properties of a one-dimensional photonic crystal with a structure defect that represents an anisotropic nanocomposite layer sandwiched between two multilayer dielectric mirrors. The nanocomposite consists of metallic nanoscale inclusions of orientationally ordered spheroidal shape, dispersed in a transparent matrix, and is characterised by an effective resonant permittivity. Each of the two orthogonal polarisations of probe radiation corresponds to a particular plasmon resonant frequency of the nanocomposite. The problem of calculating the transmittance spectrum of the waves with s- and p-polarisations for such structures is solved. Spectral manifestation of splitting of the defect mode depending on the structure parameters and volumetric fraction of the nanospheroids is studied. The essential dependence of the position of maxima of the defect modes in the bandgap of the photonic crystal and their splitting on the incidence angle, polarisation, and the ratio of lengths of the polar and equatorial semi-axes of the spheroidal nanoparticles is shown. (photonic crystals)
Wang, Yuwen
2016-09-22
We study the dynamics of an ultrafast single photon pulse in a one-dimensional waveguide two-point coupled with a Jaynes-Cummings system. We find that for any single photon input the transmissivity depends periodically on the separation between the two coupling points. For a pulse containing many plane wave components it is almost impossible to suppress transmission, especially when the width of the pulse is less than 20 times the period. In contrast to plane wave input, the waveform of the pulse can be modified by controlling the coupling between the waveguide and Jaynes-Cummings system. Tailoring of the waveform is important for single photon manipulation in quantum informatics. © The Author(s) 2016.
Aluicio-Sarduy, E; del Valle, D G Figueroa; Kriegel, I; Scotognella, F
2015-01-01
The active tuning of the structural colour in photonic crystals by an electric field represents an effective external stimulus with impact on light transmission manipulation. In this work we present this effect in a photonic crystal device with alternating layers of Silver and Titanium dioxide nanoparticles showing shifts of around 10 nm for an applied voltage of 10 V only. The accumulation of charges at the metal/dielectric interface with applied electric field leads to an effective increase of the charges contributing to the plasma frequency in Silver. This initiates a blue shift of the Silver plasmon band with a simultaneous blue shift of the photonic band gap as a result of the change in Silver dielectric function, i.e. decrease of the effective refractive index. These results are the first demonstration of active colour tuning in Silver/TiO2 nanoparticle based photonic crystals and open the route to metal/dielectric based photonic crystals as electro-optic switches.
Directory of Open Access Journals (Sweden)
Eduardo Aluicio-Sarduy
2016-10-01
Full Text Available An electric field is employed for the active tuning of the structural colour in photonic crystals, which acts as an effective external stimulus with an impact on light transmission manipulation. In this work, we demonstrate structural colour in a photonic crystal device comprised of alternating layers of silver nanoparticles and titanium dioxide nanoparticles, exhibiting spectral shifts of around 10 nm for an applied voltage of only 10 V. The accumulation of charge at the metal/dielectric interface with an applied electric field leads to an effective increase of the charges contributing to the plasma frequency in silver. This initiates a blue shift of the silver plasmon band with a simultaneous blue shift of the photonic band gap as a result of the change in the silver dielectric function (i.e. decrease of the effective refractive index. These results are the first demonstration of active colour tuning in silver/titanium dioxide nanoparticle-based photonic crystals and open the route to metal/dielectric-based photonic crystals as electro-optic switches.
Institute of Scientific and Technical Information of China (English)
XIANG Yuan-jiang; DAI Xiao-yu; WEN Shuang-chun
2007-01-01
School of Computer and Communication, Hunan University, Changsha 410082, ChinaThe photonic band gap structure of 1D photonic crystal with a negative index medium defect layer is studied by using the transfer matrix method. Investigations show that the introdution of negative index medium defect layer and the increase of the negative index value will result in an extension of the band gap. Moreover, by increasing the negative index, the width of defect layer and the numbers of period photonic crystal, the width of defect modes will be narrowed, which is advantaged to obtain optical filters with narrow band. Finally, the effects of absorption on the properties of band gap and on defect modes have been discussed.
Energy Technology Data Exchange (ETDEWEB)
Colodrero, Silvia; Mihi, Agustin; Ocana, Manuel; Miguez, Hernan [Instituto de Ciencia de Materiales de Sevilla (Spain), Consejo Superior de Investigaciones Cientificas Americo Vespucio; Haeggman, Leif; Boschloo, Gerrit; Hagfeldt, Anders [Department of Chemistry Center of Molecular Devices, Royal Institute of Technology, Stockholm (Sweden)
2009-02-16
The solar-to-electric power-conversion efficiency ({eta}) of dye-sensitized solar cells can be greatly enhanced by integrating a mesoporous, nanoparticle-based, 1D photonic crystal as a coherent scattering layer in the device. The photogenerated current is greatly improved without altering the open-circuit voltage of the cell, while keeping the transparency of the cell intact. Improved average {eta} values between 15% and 30% are attained. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
DEFF Research Database (Denmark)
Chen, T.; Han, Z. H.; Liu, J. J.
2014-01-01
exhibits high-quality factors, facilitating the realization of high sensitivity in the gas refractive index sensing. In our experiment, 6% of the change of hydrogen concentration in air, which corresponds to a refractive index change of 1.4 x 10(-5), can be steadily detected, and different gas samples can......We report in this paper terahertz gas sensing using a simple 1D photonic crystal cavity. The resonant frequencies of the cavity depend linearly on the refractive index of the ambient gas, which can then be measured by monitoring the resonance shift. Although quite easy to manufacture, this cavity...
Gómez-Urrea, H. A.; Duque, C. A.; Mora-Ramos, M. E.
2015-11-01
The properties of the optical-phonon-associated polaritonic modes that appear under oblique light incidence in 1D superlattices made of photonic materials are studied. The investigated systems result from the periodic repetition of quasiregular Rudin-Shapiro (RS) multilayer units. It is assume that the structure consists of both passive non-dispersive layers of constant refraction index and active layers of uniaxial polar materials. In particular, we consider III-V wurtzite nitrides. The optical axis of these polaritonic materials is taken along the growth direction. Maxwell equations are solved using the transfer matrix technique for all admissible values of the incidence angle.
Descrovi, Emiliano; Giorgis, Fabrizio; Dominici, Lorenzo; Michelotti, Francesco
2008-02-01
Dispersion curves of surface electromagnetic waves (SEWs) in 1D silicon nitride photonic crystals having periodic surface corrugations are considered. We experimentally demonstrate that a bandgap for SEWs can be obtained by fabricating a polymeric grating on the multilayered structure. Close to the boundary of the first Brillouin zone connected to the grating, we observe the splitting of the SEW dispersion curve into two separate branches and identify two regions of very low group velocity. The proper design of the structure allows the two folded branches to lie beyond the light line in a wide spectral range, thus doubling the density of modes available for SEWs and avoiding light scattering.
Energy Technology Data Exchange (ETDEWEB)
Ben Ali, N; Kanzari, M, E-mail: naimgi2@yahoo.fr [Photovoltaic and Semiconductor Materials Laboratory, El-Manar University-ENIT PO Box 37, Le belvedere 1002-Tunis (Tunisia)
2010-11-15
By using a theoretical model based on Transfer Matrix Method (TMM) for normal incidence simulator, and for serial (S) polarisation, the slowing of light in one-dimensional (1D) hybrid (Fibonacci{sub 1}/periodic/Fibonacci{sub 2}) photonic crystals is studied at visible frequency band. Effects of the periodicity, the non-periodicity and the number of layers of each photonic structure on the slowing down of light are discussed. The higher slowing down factors was obtained by the hybrid Fibonacci{sub 1}/periodic/Fibonacci{sub 2} structures. This slowing down factors is greater than those corresponding to the periodic, the Fibonacci, the Thue-Morse and the Cantor band-gap structures. In addition this hybrid structure gives the possibility to slowing several frequencies
Directory of Open Access Journals (Sweden)
Arka Karmakar
2013-05-01
Full Text Available Bandpass filter characteristics is numerically computed for semiconductor heterostructure based onedimensional photonic crystal at different optical wavelengths by varying the structural parameters taking GaAs/AlxGa1-xAs as a suitable composition subject to normal incidence of electromagnetic wave. Transfer matrix technique is used for numerical analysis. Results are compared with conventionally used SiO2-air material system and significance improvements are observed at few desired spectra. Heterostructure provides larger passbandwidth with almost negligible ripple than conventional material system at 1330 nm or 1550 nm, which is required for present day optical communication network. Efficient tuning can be achieved by varying different layer dimensions for the preferred material composition which effectively changes the filter bandwidth in either side of the central wavelength, but it cost generation of ripples for the conventional system.
Xu, Kun-Yuan; Zheng, Xiguang; Li, Cai-Lian; She, Wei-Long
2005-06-01
The band structures of one-dimensional photonic crystals containing a defect layer with a negative refractive index are studied, showing that the defect modes possess three types of dispersion: positive, zero, and negative types. Based on these three types of dispersion, practical designs for large incident angle filters without polarization effect and for narrow frequency and sharp angular filters are suggested. Moreover, the splitting of one degenerate defect mode into multiple defect modes is observed in the band gap when the parameters of the defect layer vary. This mode splitting phenomenon can be used to design multiple channeled filters or filters with a rectangular profile. The dispersion multiplicity of the defect modes can be understood by an approximate formula, and the critical condition for the defect mode splitting is also analyzed. Based on these analyses, practical optimization design of omnidirectional filter is also suggested.
Institute of Scientific and Technical Information of China (English)
Munazza Zulfiqar Ali; Tariq Abdullah
2008-01-01
We investigate the effects of introducing a defect layer in a one-dimensional photonic crystal containing single negative material layers on the transmission properties.The width of the defect layer js taken to be the same or smaller than the period of the structure.Different cases of the defect layer being linear or nonlinear and double positive or double negative are discussed.It is found that only a nonlinear double negative layer givas rises to a localized mode within the zero-φeff gap in this kind of structure.It is also shown that the important characteristics of the nonlinear defect mode such as its frequency,its FWHM and the threshold of the associated bistability can be controlled by changing the widths of the defect layer and the host layers.
Wang, Qichao; Wang, Jiachun; Zhao, Dapeng; Zhang, Jikui; Li, Zhigang; Chen, Zongsheng; Zeng, Jie; Miao, Lei; Shi, Jiaming
2016-11-01
We propose a new method to disclose the camouflaged targets coated with far infrared/CO2 laser stealth-compatible coating by utilizing terahertz (THz) radar. A coating based on one-dimensional photonic crystal (1DPC) with a defect mode is specially designed and successfully prepared, which possesses a high reflectivity in 8-14 μm waveband and a low reflectivity at 10.6 μm, by alternating thin films of Ge, ZnSe and Si. The propagation characteristic of 0.3-2 THz wave at incident angle from 0° to 80° in such PC coating is investigated theoretically based on characteristic matrix method. The maximal transmittance is up to 92%, and the absorptivity keeps lower than 0.5% over the whole band. The results are verified by experiments, which demonstrate the feasibility of using THz radar to detect the targets covered with such stealth-compatible coatings.
Bouazzi, Y.; Kanzari, M.
2012-06-01
In this work, a new type of optical filter using photonic band gap materials has been suggested. Indeed, a combination of periodic H(LH)J and Rudin-Shapiro quasi-periodic one-dimensional photonic multilayer systems (RSM) were used. SiO2 (L) and TiO2 (H) were chosen as two elementary layers with refractive indexes nL = 1.45 and nH = 2.30 respectively. The study configuration is H(LH)J[RSM]PH(LH)J, which forms an effective Fabry-Perot filter (FPF), where J and P are respectively the repetition number of periodic and (RSM) stacks. We have numerically investigated by means of transfer-matrix approach the transmission properties in the visible spectral range of FPF system. We show that the number and position of resonator peaks are dependent on the (RSM) repetition number P and incidence angle of exciting light. The effect of these two parameters for producing an improved polychromatic filter with high finesse coefficient (F) and quality factor (Q) is studied in details.
Institute of Scientific and Technical Information of China (English)
高永芳; 时家明; 赵大鹏
2011-01-01
利用特征矩阵法,分别研究了不同偏振方式的波入射到光子晶体时,光子晶体的禁带随入射角度的变化.结果表明:不论是TM波入射还是TE波入射,随着入射角度的增大,光子晶体的带隙都向短波方向移动;TM波入射时,光子晶体的带隙随入射角度的增大而减小,而以TE波入射光子晶体时,随着入射角度的增大,光子晶体的带隙逐渐增大.%The relationship of photonic band gap characteristics of photonic crystals and the different incidence angle were researched by characteristic matrix method. The result shows that the photonic band gap of 1D photonic crystals moves towards shortwave when incidence angle increase, no matter the incidence wave is TM wave or TE wave; the photonic band gap of 1D photonic crystals of TM wave decreases when the incidence angle increase, the photonic band gap of 1 D photonic crystals of TE wave increases when the incidence angle increase. This work provides a valuable reference to the design and application of infrared camouflage using one dimensional photonic crystals.
Fabrication of One-Dimensional Photonic Crystals PAA/TiO2%PAA/TiO2一维光子晶体的制备
Institute of Scientific and Technical Information of China (English)
张玉琦; 魏清渤; 王俏; 宋延卫
2012-01-01
以聚丙烯酸(PAA)和TiO2纳米粒子为电介质材质,采用旋涂技术制备了PAA/TiO2一维光子晶体.用扫描电子显微镜对其层层沉积的结构进行了表征,用紫外可见反射光谱对光子禁带进行了研究,考察了光子禁带与成膜参数的关系.结果表明,通过调控旋涂速度或者PAA溶液质量分数,可以制备出具有不同光子禁带的PAA/TiO2一维光子晶体,且光子禁带随旋涂速度的加快线性蓝移、随PAA溶液质量分数的增大线性红移.%One-dimensional photonic crystals (1D-PCs) PAA (poly acrylic acid)/TiO2 were fabricated by spin-coating technique. The layer-by-layer deposition structure of the 1D-PCs was characterized by scanning e-lectron microscopy. The photonic stopbands of the 1D-PCs were measured by UV-visible reflectance spectrum. The relationship between photonic stopbands and experimental parameters were also studied. The results demonstrated that the 1D-PCs with different stopbands could be obtained from controlling spin-coating or speed mass fraction of PAA solution. The stopbands had a linearly blue shift with spin-coating speed increasing,and had a linearly red shift with the mass fraction of PAA solution increasing.
Singh, Bipin K.; Pandey, Praveen C.
2014-12-01
In this paper, we present the investigation on the photonic localization and band gaps in quasi-periodic photonic crystals containing graded index materials using a transfer matrix method in region 150-750 THz of the electromagnetic spectrum. The graded layers have a space dispersive refractive index, which vary in a linear and exponential fashion as a function of the depth of layer. The considered quasiperiodic structures are taken in the form of Thue-Morse and Double-Periodic sequences. The grading profile in the layers affects the position of reflection dips and forbidden bands, and frequency region of the bands. We observed that vast number of forbidden band gaps and dips are developed in its reflection spectra by increasing the number of quasi-periodic generation. Moreover, we compare the total forbidden bandwidths with increasing the generation of the quasi-periodic sequences for the structures with linear and exponential graded layer. Results show that the different graded profiles with same boundary refractive index can change the position of localization modes, number of photonic bands and change the frequency region of the bands. Therefore, we can achieve suitable photonic band gaps and modes by choosing the different gradation profiles of the refractive index and generation of the quasi-periodic sequences.
光子晶体增强石墨烯THz吸收%Terahertz absorption of graphene enhanced by one-dimensional photonic crystal
Institute of Scientific and Technical Information of China (English)
谢凌云; 肖文波; 黄国庆; 胡爱荣; 刘江涛
2014-01-01
研究了光子晶体表面石墨烯在应力赝磁场作用下的太赫兹(THz)吸收。由于应力赝磁场的存在使得石墨烯中电子出现朗道能级并对THz波呈现出一个较强的吸收。而光子晶体和石墨烯形成了表面微腔结构使得石墨烯对THz波的吸收比无光子晶体时增强了将近四倍。且可以通过改变应力赝磁场和间隔层厚度来调控石墨烯的THz吸收。%The terahertz (THz) radiation absorption of graphene layers in a pseudomagnetic field, prepared on top of a one-dimensional photonic crystal (1DPC), is investigated theoretically. Discrete Landau levels can be found in graphene in a pseudomagnetic field. Strong THz transitions may be found between the discrete Landau levels. The THz absorption of graphene can also be tuned by varying either pseudomagnetic field or the distance between the graphene and the 1DPC.
Institute of Scientific and Technical Information of China (English)
郭立帅
2012-01-01
The properties of band - gap of one - dimensional doped photonic crystal are studied by using numerical- ly method based on the transfer matrix method. The result shows that a narrow conduction band appears in the cen- tre of forbidden band in one - dimensional doped photonic crystal. The depth of conduction band appears in the centre of forbidden band has a maximum, which was caused by the number of layers of the second half of impurity where the first one was fixed. It shows that the forbidden band center＇s conduction band depth was still biggest by means of changing basic level thickness.%基于传输矩阵法,数值研究了掺杂一维光子晶体带隙特征。研究表明：一维掺杂光晶体禁带中心位置出现一个极窄的导带,当杂质前半部分层数给定时,后半部分总存在一个层数,使得禁带中心导带的深度达到最大,在此基础上通过改变基本层厚度发现,禁带中心的导带深度仍然最大,我们可以通过改变基本层厚度厚度,让特定波长的光顺利通过。
Energy Technology Data Exchange (ETDEWEB)
Kerstein, A.R. [Sandia National Lab., Livermore, CA (United States)
1996-12-31
One-Dimensional Turbulence is a new turbulence modeling strategy involving an unsteady simulation implemented in one spatial dimension. In one dimension, fine scale viscous and molecular-diffusive processes can be resolved affordably in simulations at high turbulence intensity. The mechanistic distinction between advective and molecular processes is thereby preserved, in contrast to turbulence models presently employed. A stochastic process consisting of mapping {open_quote}events{close_quote} applied to a one-dimensional velocity profile represents turbulent advection. The local event rate for given eddy size is proportional to the velocity difference across the eddy. These properties cause an imposed shear to induce an eddy cascade analogous in many respects to the eddy cascade in turbulent flow. Many scaling and fluctuation properties of self-preserving flows, and of passive scalars introduced into these flows, are reproduced.
Stationary one-dimensional dispersive shock waves
Kartashov, Yaroslav V
2011-01-01
We address shock waves generated upon the interaction of tilted plane waves with negative refractive index defect in defocusing media with linear gain and two-photon absorption. We found that in contrast to conservative media where one-dimensional dispersive shock waves usually exist only as nonstationary objects expanding away from defect or generating beam, the competition between gain and two-photon absorption in dissipative medium results in the formation of localized stationary dispersive shock waves, whose transverse extent may considerably exceed that of the refractive index defect. One-dimensional dispersive shock waves are stable if the defect strength does not exceed certain critical value.
Institute of Scientific and Technical Information of China (English)
范伟丽; 董丽芳
2012-01-01
A tunable one-dimensional plasma photonic crystal has been obtained in argon dielectric barrier discharge with two water electrodes at atmospheric pressure. The dispersion relation of the plasma photonic crystals is studied by solving a stationary Maxwell wave equation with a method analogous to Kronig-Penney's problem in quantum mechanics. Based on the experimental data, the influence of the parameters including the lattice constant, the length ratio of the plasma and dielectric and electron density on the band diagrams of the plasma photonic crystals is discussed. Results show that the position of the photonic bands is lowered and the phase velocity is reduced when the lattice constant is increased. For the same lattice constants, larger ratio of the plasma with the dielectric leads to the increase of the band gaps and higher band frequencies. The plasma photonic crystals will show wide band gaps when the electron density is larger than 1020 m-3.%在双水电极大气压氩气介质阻挡放电中获得了一维可调等离子体光子晶体.通过类似于量子力学Kronig-Penney模型求解周期势的方法,求解Maxwell方程得到了一维等离子光子晶体的色散关系.结合实验数据,理论模拟了晶格常数、等离子体与介质的厚度比、电子密度等不同参数对等离子体光子晶体带隙的影响.结果表明:等离子体光子晶体晶格常数的增大导致能级位置降低,相速度减小；在相同的晶格常数下,等离子体填充比增大时,带隙位置将略有上升且光子带隙数目增加；当电子密度大于1020 m-3时,等离子体光子晶体具有显著禁带宽度.
Institute of Scientific and Technical Information of China (English)
刘名扬; 贺珍妮; 张向东
2013-01-01
Transfer matrix method is used to analyze the transmission spectra of one dimensional photon-ic crystals with negative refractive index material and positive refractive index material alternant struc-ture .The bang gaps and dispersive relation of one dimensional photonic crystal are analyzed .The gener-al Bragg gaps and the resonant gap of low frequency exist in the photonic crystal .We also research local-ization of electromagnetic waves in one-dimension random system containing the left-handed material .%采用传递矩阵的方法研究了由正折射率材料和负折射率材料交替排列组成的一维光子晶体结构的透射谱，并对其能带结构和色散关系进行分析，这种正负折射率光子晶体不仅存在一般的布拉格禁带，还存在低频共振禁带。本文也对含左手材料的一维无序结构的局域化进行了分析研究。
One-Dimensionality and Whiteness
Calderon, Dolores
2006-01-01
This article is a theoretical discussion that links Marcuse's concept of one-dimensional society and the Great Refusal with critical race theory in order to achieve a more robust interrogation of whiteness. The author argues that in the context of the United States, the one-dimensionality that Marcuse condemns in "One-Dimensional Man" is best…
One-Dimensionality and Whiteness
Calderon, Dolores
2006-01-01
This article is a theoretical discussion that links Marcuse's concept of one-dimensional society and the Great Refusal with critical race theory in order to achieve a more robust interrogation of whiteness. The author argues that in the context of the United States, the one-dimensionality that Marcuse condemns in "One-Dimensional Man" is best…
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Yassine Bouazzi
2012-10-01
Full Text Available The last decades have witnessed the growing interest in the use of photonic crystal as a new material that can be used to control electromagnetic wave. Actually, not only the periodic structures but also the quasi-periodic systems have become significant structures of photonic crystals. This work deals with optical properties of dielectric Thue-Morse multilayer and Period-Doubling multilayer. We use the so-called Transfer Matrix Method (TMM to determine the transmission spectra of the structures. Based on the representation of the transmittance spectra in the visible range a comparative analysis depending on the iteration number, number of layers and incidence angle is presented.
One-Dimensional Function Photonic Crystals%一维函数光子晶体的禁带特性理论
Institute of Scientific and Technical Information of China (English)
王清才; 王岩; 王光怀
2012-01-01
提出了一种新型函数光子晶体,其折射率是一个空间位置函数.在费马原理的基础上,利用传输矩阵理论研究了光子晶体介质层的折射率、周期数、入射角等对光子晶体带隙变化的影响.为灵活实现某特定带隙的光子晶体的制备提供了理论依据.%A new kind of function photonic crystals is presented,whose refractive index is a function of space position.Based on Fermat principle and by using the transfer matrix theory,the influences of the refractive index of photonic crystal dielectric layer,number of cycles,and angle of incidence on the band structure of photonic crystals are studied.This study provides a theoretical basis of the preparation of photonic crystals with specific band gap.
Vincenti, Maria Antonietta; Trevisi, Simona; De Sario, Marco; Petruzzelli, Vincenzo; D'Orazio, Antonella; Prudenzano, Francesco; Cioffi, Nicola; de Ceglia, Domenico; Scalora, Michael
2008-03-01
In this paper we report a numerical study of a palladium-based metallo-dielectric photonic band gap structure for the purpose of detecting H2. In particular, and as an example, we will explore applications to the diagnosis of lactose malabsorption, more commonly known as lactose intolerance condition. This pathology occurs as a result of an incomplete absorption or digestion of different substances, causing an increased spontaneous emission of H2 in human breath. Palladium is considered in order to exploit its well known ability to absorb hydrogen spontaneously. The proposed structure is particularly able to detect the lactose malabsorption level of the patient with relatively high sensitivity and rapidity.
Scotognella, Francesco
2016-01-01
The employment of magneto-optical materials to fabricate photonic crystals gives the unique opportunity to achieve optical tuning with the magnetic field. In this study we have simulated the transmission spectrum of a microcavity in which the Bragg reflectors are made with silica (SiO2) and yttria (Y2O3) and the defect layer is made with TGG (Tb3Ga5O12). We show that the application of an external magnetic field results in a tuning of the defect mode of the microcavity. In the simulations we have considered the wavelength dependence of the refractive indexes and the Verdet constants of the materials. A tuning of the defect mode of about 22 nm with a magnetic field of 5 T, at low temperature (8 K), is demonstrated. Furthermore, we discuss the possibility to tune a microcavity with disordered photonic structures as reflectors. In the presence of the magnetic field such microcavity shows a shift of resonances in a broad range of wavelengths.
Institute of Scientific and Technical Information of China (English)
杨红卫; 慕振峰; 姜舒宁
2012-01-01
Transmission coefficient of the one-dimensional photonic crystal with various dielectric materials is simulated by using precise integration, and simulation results are analyzed. Photonic crystal is divided into different sections. Potential energy of the section and mixed energy of the section are introduced. The export stiffness matrix of each section can be obtained by using precise integration, and then each stiffness matrix is combined. The problem can be solved by imposing boundary conditions on the stiffness matrix. The curves of lose rate D are drawn to check the validity and accuracy of the numerical solution. The simulation results show that this method is accurate, efficient and applicable for the simulation of one-dimensional photonic crystal.%应用精细积分法对含各种介质材料的一维光子晶体进行了数值模拟,并对结果进行了分析.计算时将光子晶体分成不同的区段,引入区段势能和区段混合能,利用精细积分法求出各个区段的出口刚度矩阵,然后将各个区段的刚度矩阵合并,再结合边界条件便可求解问题.利用透射率和反射率之间的关系,判断了本算法的准确度,数值计算结果表明,对于一维光子晶体的数值模拟,此方法准确、有效、适用性强.
One-Dimensional Anisotropic Band Gap Structure
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The band gap structure of one-dimensional anisotropic photonic crystal has been studied by means of the transfer matrix formalism. From the analytic expressions and numeric calculations we see some general characteristics of the band gap structure of anisotropic photonic crystals, each band separates into two branches and the two branches react to polarization sensitively. In the practical case of oblique incidence, gaps move towards high frequency when the angle of incidence increases. Under some special conditions, the two branches become degenerate again.
Institute of Scientific and Technical Information of China (English)
巴诺; 王磊; 张岩
2014-01-01
基于电磁感应透明技术，将相干耦合的Tripod型原子俘获在一维光晶格中并使其呈高斯型分布，由于介质的折射率被一维光晶格周期性调制，从而实现动态调控的三光子带隙结构。通过求解光场与原子相互作用密度矩阵方程以及光波在周期性介质中散射的传输矩阵方程，计算出探测场在相干驱动介质中的稳态反射谱和透射谱。计算结果表明：光子带隙的位置、宽度以及反射率可以通过改变两个耦合场的失谐、强度和几何布拉格失谐来调谐。%Using the technique of electromagnetically induced transparency, three photonic bandgaps can be established and manipulated at any time due to the refraction modulated periodically by the one-dimensional optical lattice in a tripod atomic system which is trapped in a one-dimensional optical lattice with a Gaussian density distribution. Using the density-matrix equations to describe the interaction between laser and atoms and the transfer-matrix equation to describe the scattering of light waves in periodic media, we can obtain the steady reflection and transmission spectra. It can be found that the position and width as well as the reflectivity of the photonic band-gap could be tuned by changing the detunings and intensities of the coupling fields and the geometric Bragg detuning.
Institute of Scientific and Technical Information of China (English)
谌静; 唐吉玉; 韩培德; 闫凌云; 陈俊芳
2008-01-01
Theoretical calculations via the transfer matrix method (TMM) are performed to investigate optical properties of one-dimensional semiconductor-organic photonic crystals (SOPC) with periodic conjugated polymer (3-octylthio-phenes,P3OT)/AIN multilayer structure. The SOPC presents incomplete photonic band gap behavior in the UV region. P3OT/AIN multilayers with two pairs of 30nm-P3OT and 30nm-AIN layers exhibit a photonic band gap at a central wavelength of about 275nm,and the highest reflectivity reaches 98%. Furthermore,the band gaps are confirmed to be tunable by adjusting the lattice period and the filling fraction. As a consequence, the SOPC is important for achieving materials with an incomplete band gap in the UV region.%理论上采用转移矩阵法研究了具有P30T/AIN多层膜结构的一维半导体-有机物型光子晶体的光学特性.计算结果表明:由厚度分别为30,30nm的P30T,AIN薄膜组成的多层膜结构,在中心波段为275nm处有一不完全的光子带隙存在,反射率最高可达98%;而且可以通过调整薄膜厚度、填充比等参数对光子带隙的位置、反射强度进行调制.因此,这种一维半导体一有机物型光子晶体对在紫外波段获得具有一定功能的光子晶体具有重要的指导意义.
One-dimensional hypersonic phononic crystals.
Gomopoulos, N; Maschke, D; Koh, C Y; Thomas, E L; Tremel, W; Butt, H-J; Fytas, G
2010-03-10
We report experimental observation of a normal incidence phononic band gap in one-dimensional periodic (SiO(2)/poly(methyl methacrylate)) multilayer film at gigahertz frequencies using Brillouin spectroscopy. The band gap to midgap ratio of 0.30 occurs for elastic wave propagation along the periodicity direction, whereas for inplane propagation the system displays an effective medium behavior. The phononic properties are well captured by numerical simulations. The porosity in the silica layers presents a structural scaffold for the introduction of secondary active media for potential coupling between phonons and other excitations, such as photons and electrons.
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D Aristizábal-Giraldo
2013-11-01
Full Text Available The Anderson localization of light in one-dimensional disordered photonic superlattices is theoretically studied. The system is considered to be made of alternating dispersive and nondispersive layers of different randomthickness. Dispersive slabs of the heterostructure are characterized by Drude-like frequency-dependent electric permittivities and magnetic permeabilities. Numerical results for the localization length are obtained via an analytical model, only valid in the case of weak disorder, and also through its general definition involving the transmissivity of the multilayered system. Anomalous ?4- and ?-4-dependencies of the localization length in positive-negative disordered photonic superlattices are obtained, in certain cases, in the long and short wavelength limits, respectively.La localización de Anderson de la luz en superredes fotónicas desordenadas unidimensionales es estudiada teóricamente. El sistema se considera compuesto de capas alternadas dispersivas y no dispersivas de diferentes espesores aleatorios. Las capas dispersivas de la heteroestructura están caracterizadas por permitividades eléctricas y permeabilidades magnéticas tipo Drude dependientes de la frecuencia. Los resultados numéricos para la longitud de la localización son obtenidos mediante un modelo analítico, solo válido en caso de desorden débil, y también a través de la definición general que involucra la transmisividad del sistema multicapas. Las dependencias anómalas ?4 y ?-4 de la longitud de localización en superredes fotónicas desordenadas son obtenidas, en ciertos casos, en los límites de longitudes de onda larga y corta, respectivamente.
One Dimensional Ballistic Electron Transport
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Thomas K J
2009-10-01
Full Text Available Research in low-dimensional semiconductor systems over the last three decades has been largely responsible for the current progress in the areas of nanoscience and nanotechnology. The ability to control and manipulate the size, the carrier density, and the carrier type in two-, one-, and zero- dimensional structures has been widely exploited to study various quantum transport phenomena. In this article, a brief introduction is given to ballistic electron transport in one-dimensional quantum wires.
Institute of Scientific and Technical Information of China (English)
范伟丽; 张新立; 董丽芳
2011-01-01
In order to investigate the influences of the dielectric constant on the plasma photonic crystals, the dispersion relation of one-dimensional plasma photonic crystals has been studied by solving a stationary Maxwell wave equation with a method analogous to Kronig-Penney's problem in quantum mechanics. The results showed that the dielectric constant affected greatly on both of the band gap width and the band edge frequencies. The bandgaps became more obvious with an increasing of the dielectric constant,and the changes of the first and second band gap widths were different. In addition, the cut-off frequency of this plasma photonic crystal as well as the edge frequency of the second band gap was decreased with an increasing of the dielectric constants.%为深入研究介电常数对等离子体光子晶体性质的影响,本工作从Maxwell方程出发,采用类似于量子力学Kronig-Penney模型求解周期势的方法,对一维等离子体光子晶体介质层介电常数对能带结构的影响进行了讨论.研究发现:介电常数的大小对等离子体光子晶体的禁带宽度和能级位置均具有重要影响.随介电常数的增加,等离子体光子晶体的带隙特征越加明显,但第一、二级禁带宽度随介电常数的变化规律不同.此外,等离子体光子晶体的截止频率以及第二级光子禁带的边缘频率随介电常数的增大而减小.
Institute of Scientific and Technical Information of China (English)
李建锋; 王建; 周峰; 王成伟
2011-01-01
基于二流体电子模型和平面波展开法,计算了一维Al/SrF2超导体-电介质光子晶体的能带结构.结果表明:随着超导层厚度的增加,第一光子带隙中心频率和截止频率均发生蓝移,且第一带隙宽度逐渐增加到一个峰值后又逐渐变窄.更重要的是,在低于临界温度的超低温环境中,温度的微小变化,对该类光子晶体的带隙宽度、中心频率以及截止频率均有明显的调制作用.%The photonic band structure of one - dimensional (1D) Al/SrF2 low temperature superconductor - dielectric photonic crystal (PC) was calculated numerically based on the plane - wave expansion method. The two - fluid model was adopted to describe the dielectric properties of the low temperature superconducting system. The simulation results clearly reveal both photonic band gap and a cutoff frequency can be modulated through the thicknesses of the superconductor layers. It is more interesting that with a small variation of ambient temperature, the photonic band gap and a cutoff frequency can be obviously modulated. This work would be of value in the design of photoelectric device for potential applications in extreme low - temperature environment.
One Dimensional Locally Connected S-spaces
Kunen, Joan E Hart Kenneth
2007-01-01
We construct, assuming Jensen's principle diamond, a one-dimensional locally connected hereditarily separable continuum without convergent sequences. The construction is an inverse limit in omega_1 steps, and is patterned after the original Fedorchuk construction of a compact S-space. To make it one-dimensional, each space in the inverse limit is a copy of the Menger sponge.
Coherent Backscattering of Light Off One-Dimensional Atomic Strings
Sørensen, H. L.; Béguin, J.-B.; Kluge, K. W.; Iakoupov, I.; Sørensen, A. S.; Müller, J. H.; Polzik, E. S.; Appel, J.
2016-09-01
We present the first experimental realization of coherent Bragg scattering off a one-dimensional system—two strings of atoms strongly coupled to a single photonic mode—realized by trapping atoms in the evanescent field of a tapered optical fiber, which also guides the probe light. We report nearly 12% power reflection from strings containing only about 1000 cesium atoms, an enhancement of 2 orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fiber connection between several distant 1D atomic crystals.
Exactly solvable one-dimensional inhomogeneous models
Energy Technology Data Exchange (ETDEWEB)
Derrida, B.; France, M.M.; Peyriere, J.
1986-11-01
The authors present a simple way of constructing one-dimensional inhomogeneous models (random or quasiperiodic) which can be solved exactly. They treat the example of an Ising chain in a varying magnetic field, but their procedure can easily be extended to other one-dimensional inhomogeneous models. For all the models they can construct, the free energy and its derivatives with respect to temperature can be computed exactly at one particular temperature.
Coherent backscattering of light off one-dimensional atomic strings
Sørensen, H L; Kluge, K W; Iakoupov, I; Sørensen, A S; Müller, J H; Polzik, E S; Appel, J
2016-01-01
Bragg scattering, well known in crystallography, has become a powerful tool for artificial atomic structures such as optical lattices. In an independent development photonic waveguides have been used successfully to boost quantum light-matter coupling. We combine these two lines of research and present the first experimental realisation of coherent Bragg scattering off a one-dimensional (1D) system - two strings of atoms strongly coupled to a single photonic mode - realised by trapping atoms in the evanescent field of a tapered optical fibre (TOF), which also guides the probe light. We report nearly 12% power reflection from strings containing only about one thousand caesium atoms, an enhancement of more than two orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fibre connection between several distant 1D atomic crystals.
One-dimensional oscillator in a box
Energy Technology Data Exchange (ETDEWEB)
Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (UNLP, CCT La Plata-CONICET), Division Quimica Teorica, Blvd 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)], E-mail: paolo@ucol.mx, E-mail: fernande@quimica.unlp.edu.ar
2010-01-15
We discuss a quantum-mechanical model of two particles that interact by means of a harmonic potential and are confined to a one-dimensional box with impenetrable walls. We apply perturbation theory to the cases of different and equal masses and analyse the symmetry of the states in the latter case. We compare the approximate perturbation results with accurate numerical ones.
QUASI-ONE DIMENSIONAL CLASSICAL FLUIDS
Directory of Open Access Journals (Sweden)
J.K.Percus
2003-01-01
Full Text Available We study the equilibrium statistical mechanics of simple fluids in narrow pores. A systematic expansion is made about a one-dimensional limit of this system. It starts with a density functional, constructed from projected densities, which depends upon projected one and two-body potentials. The nature of higher order corrections is discussed.
Highly conducting one-dimensional solids
Evrard, Roger; Doren, Victor
1979-01-01
Although the problem of a metal in one dimension has long been known to solid-state physicists, it was not until the synthesis of real one-dimensional or quasi-one-dimensional systems that this subject began to attract considerable attention. This has been due in part to the search for high temperature superconductivity and the possibility of reaching this goal with quasi-one-dimensional substances. A period of intense activity began in 1973 with the report of a measurement of an apparently divergent conduc tivity peak in TfF-TCNQ. Since then a great deal has been learned about quasi-one-dimensional conductors. The emphasis now has shifted from trying to find materials of very high conductivity to the many interesting problems of physics and chemistry involved. But many questions remain open and are still under active investigation. This book gives a review of the experimental as well as theoretical progress made in this field over the last years. All the chapters have been written by scientists who have ...
Institute of Scientific and Technical Information of China (English)
乌日娜; 闫彬; 王彦华; 徐送宁; 闫秀生; 岱钦
2011-01-01
制作了SiO2/TiO2多层膜结构一维光子晶体,研究了其光子禁带特性.通过测量红外透射谱,分析了入射线偏振方向、入射角度以及引入缺陷层对光子禁带的影响.随着入射角度的增大,在TE模式和TM模式线偏振光下,光子禁带边沿产生蓝移现象.引入TEB30A型向列相液晶缺陷后,光子禁带中在波长约为l810nm(TE模式)和182lam(TM模式)处出现了透射峰.利用传输矩阵理论,模拟计算了光子晶体透射谱,并对实验结果进行了深入分析.无缺陷时,随着入射角增大,薄膜的光学厚度减小,光子禁带边沿蓝移.引入液晶缺陷后,光子禁带中产生特定的缺陷态,和缺陷态频率相吻合的光子被局域在缺陷位置,禁带中出现透射峰.由于两种模式线偏振光下的液晶层光学厚度不同,透射峰位置也不同.%One-dimensional (1D) multilayer photonic crystal (PC) with SiO2/TiO2 was designed and fabricated.The characteristics of photonic band gap (PBG) were investigated.The influences of the linearly polarized light, the incident angle and the introduced defect layers on the PBG were analyzed by measuring the infrared transmission spectra.The edge of PBG shifted to shorter wavelength when the incident angles of linearly polarized light of TE mode and TM mode increased.Transmission peaks appeared in photonic band gap and their center wavelengths were approximately 1810 nm(TE) and 1821 nm (TM) if defect layer of nematic liquid crystal TEB30A was introduced.The transmission spectrtun of PC was simulated with the transfer matrix theory.The experimental results show that when there is no defect layer, the increasing of the incident angle brings a decreasing of optical thickness of the film, which results in a blue shift of the PBG edge.A specific defect state is produced in the PBG when introducing the liquid crystal defect layers.The photons which have the same frequency with the defect states are localized in the defect position
One-Dimensional Simulation of Clay Drying
Directory of Open Access Journals (Sweden)
Siljan Siljan
2002-04-01
Full Text Available Drying of clay is simulated by a one-dimensional model. The background of the work is to form a better basis for investigation of the drying process in production of clay-based building materials. A model of one-dimensional heat and mass transfer in porous material is used and modified to simulate drying of clay particles. The convective terms are discretized by first-order upwinding, and the diffusive terms are discretized by central differencing. DASSL was used to solve the set of algebraic and differential equations. The different simulations show the effect of permeability, initial moisture content and different boundary conditions. Both drying of a flat plate and a spherical particle are modelled.
One-dimensional nano-interconnection formation.
Ji, Jianlong; Zhou, Zhaoying; Yang, Xing; Zhang, Wendong; Sang, Shengbo; Li, Pengwei
2013-09-23
Interconnection of one-dimensional nanomaterials such as nanowires and carbon nanotubes with other parts or components is crucial for nanodevices to realize electrical contacts and mechanical fixings. Interconnection has been being gradually paid great attention since it is as significant as nanomaterials properties, and determines nanodevices performance in some cases. This paper provides an overview of recent progress on techniques that are commonly used for one-dimensional interconnection formation. In this review, these techniques could be categorized into two different types: two-step and one-step methods according to their established process. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, the electrodeposition approach is illustrated in detail, and its potential mechanism is emphasized.
One-Dimensional Tunable Josephson Metamaterials
Butz, Susanne
2014-01-01
This thesis presents a novel approach to the experimental realization of tunable, superconducting metamaterials. Therefore, conventional resonant meta-atoms are replaced by meta-atoms that contain Josephson junctions, which renders their resonance frequency tunable by an external magnetic field. This tunability is theoretically and experimentally investigated in one-dimensional magnetic and electric metamaterials. For the magnetic metamaterial, the effective, magnetic permeability is determined.
Vectorlike representation of one-dimensional scattering
Sánchez-Soto, L L; Barriuso, A G; Monzon, J J
2004-01-01
We present a self-contained discussion of the use of the transfer-matrix formalism to study one-dimensional scattering. We elaborate on the geometrical interpretation of this transfer matrix as a conformal mapping on the unit disk. By generalizing to the unit disk the idea of turns, introduced by Hamilton to represent rotations on the sphere, we develop a method to represent transfer matrices by hyperbolic turns, which can be composed by a simple parallelogramlike rule.
Momentum Dynamics of One Dimensional Quantum Walks
Fuss, I; Sherman, P J; Naguleswaran, S; Fuss, Ian; White, langord B.; Sherman, Peter J.; Naguleswaran, Sanjeev
2006-01-01
We derive the momentum space dynamic equations and state functions for one dimensional quantum walks by using linear systems and Lie group theory. The momentum space provides an analytic capability similar to that contributed by the z transform in discrete systems theory. The state functions at each time step are expressed as a simple sum of three Chebyshev polynomials. The functions provide an analytic expression for the development of the walks with time.
One-dimensional nanostructures principles and applications
Zhai, Tianyou
2012-01-01
Reviews the latest research breakthroughs and applications Since the discovery of carbon nanotubes in 1991, one-dimensional nanostructures have been at the forefront of nanotechnology research, promising to provide the building blocks for a new generation of nanoscale electronic and optoelectronic devices. With contributions from 68 leading international experts, this book reviews both the underlying principles as well as the latest discoveries and applications in the field, presenting the state of the technology. Readers will find expert coverage of all major classes of one-di
Distibines, New One-Dimensional Materials.
2014-09-26
Diarsines, Distibines * and Dibismuthines," XI International Conference on Organometallic * Chemistry , Pine Mountain, Georgia, October 1983. (vi...D-R158 534 DISTIINES NEW ONE-DIMENSIONAL MTERILS(U) ICHIGAN i/UNJY ANN ARBOR DEPT OF CHEMISTRY A J ASHE 17 NAY 85 RFOSR-TR-85-9592 RFOSR-81-909 N...ADDRESS (Ci, Stett, and ZIP Code) Department of Chemistry , University Building 410, Bolling AFS, D.C. of Michigan, Ann Arbor, MI 48109 20332-6448 Sa
Localized chaos in one-dimensional hydrogen
Energy Technology Data Exchange (ETDEWEB)
Humm, D.C.; Saltz, D.; Nayfeh, M.H. (Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (USA))
1990-08-01
We calculate the response of hydrogen to the presence of both a strong dc electric field (necessary to isolate a nearly one-dimensional motion) and a strong radiation field of higher frequency than the binding energy of the system, a regime that has not previously been examined by theory or experiment. We determine the classical ionization threshold, the quantum-delocalization threshold, and the threshold of {ital n} mixing due to chaotic effects. The analysis indicates that the dc field can have a dramatic effect on the quantum localization of classically chaotic diffusion, changing the delocalization threshold by more than an order of magnitude. Moreover, this system provides a large spectral region in which quantum-mechanical localization inhibits classical chaotic diffusion. This theory is well suited to experimental testing.
One-dimensional spinon spin currents
Hirobe, Daichi; Sato, Masahiro; Kawamata, Takayuki; Shiomi, Yuki; Uchida, Ken-Ichi; Iguchi, Ryo; Koike, Yoji; Maekawa, Sadamichi; Saitoh, Eiji
2017-01-01
Quantum spin fluctuation in a low-dimensional or frustrated magnet breaks magnetic ordering while keeping spin correlation. Such fluctuation has been a central topic in magnetism because of its relevance to high-Tc superconductivity and topological states. However, utilizing such spin states has been quite difficult. In a one-dimensional spin-1/2 chain, a particle-like excitation called a spinon is known to be responsible for spin fluctuation in a paramagnetic state. Spinons behave as a Tomonaga-Luttinger liquid at low energy, and the spin system is often called a quantum spin chain. Here we show that a quantum spin chain generates and carries spin current, which is attributed to spinon spin current. This is demonstrated by observing an anisotropic negative spin Seebeck effect along the spin chains in Sr2CuO3. The results show that spin current can flow even in an atomic channel owing to long-range spin fluctuation.
Collapsing of chaos in one dimensional maps
Yuan, Guocheng; Yorke, James A.
2000-02-01
In their numerical investigation of the family of one dimensional maps f l(x)=1-2∣x∣ l, where l>2 , Diamond et al. [P. Diamond et al., Physica D 86 (1999) 559-571] have observed the surprising numerical phenomenon that a large fraction of initial conditions chosen at random eventually wind up at -1, a repelling fixed point. This is a numerical artifact because the continuous maps are chaotic and almost every (true) trajectory can be shown to be dense in [-1,1]. The goal of this paper is to extend and resolve this obvious contradiction. We model the numerical simulation with a randomly selected map. While they used 27 bit precision in computing f l, we prove for our model that this numerical artifact persists for an arbitrary high numerical prevision. The fraction of initial points eventually winding up at -1 remains bounded away from 0 for every numerical precision.
Superfluid helium-4 in one dimensional channel
Kim, Duk Y.; Banavar, Samhita; Chan, Moses H. W.; Hayes, John; Sazio, Pier
2013-03-01
Superfluidity, as superconductivity, cannot exist in a strict one-dimensional system. However, the experiments employing porous media showed that superfluid helium can flow through the pores of nanometer size. Here we report a study of the flow of liquid helium through a single hollow glass fiber of 4 cm in length with an open id of 150 nm between 1.6 and 2.3 K. We found the superfluid transition temperature was suppressed in the hollow cylinder and that there is no flow above the transition. Critical velocity at temperature below the transition temperature was determined. Our results bear some similarity to that found by Savard et. al. studying the flow of helium through a nanohole in a silicon nitrite membrane. Experimental study at Penn State is supported by NSF Grants No. DMR 1103159.
One-dimensional reduction of viscous jets
Pitrou, Cyril
2015-01-01
We build a general formalism to describe thin viscous jets as one-dimensional objects with an internal structure. We present in full generality the steps needed to describe the viscous jets around their central line, and we argue that the Taylor expansion of all fields around that line is conveniently expressed in terms of symmetric trace-free tensors living in the two dimensions of the fiber sections. We recover the standard results of axisymmetric jets and we report the first and second corrections to the lowest order description, also allowing for a rotational component around the axis of symmetry. When applied to generally curved fibers, the lowest order description corresponds to a viscous string model whose sections are circular. However, when including the first corrections we find that curved jets generically develop elliptic sections. Several subtle effects imply that the first corrections cannot be described by a rod model, since it amounts to selectively discard some corrections. However, in a fast...
One-dimensional Vlasov-Maxwell equilibria
Greene, John M.
1993-06-01
The purpose of this paper is to show that the Vlasov equilibrium of a plasma of charged particles in an electromagnetic field is closely related to a fluid equilibrium, where only a few moments of the velocity distribution of the plasma are considered. In this fluid equilibrium the electric field should be calculated from Ohm's law, rather than the Poisson equation. In practice, only one-dimensional equilibria are treated, because the symmetry makes this case tractable. The emphasis here is on gaining a better understanding of the subject, but an alternate way of doing the calculations is suggested. It is shown that particle distributions can be found that are consistent with any reasonable electromagnetic field profile.
SUSY-inspired one-dimensional transformation optics
Miri, Mohammad-Ali; Christodoulides, Demetrios N
2014-01-01
Transformation optics aims to identify artificial materials and structures with desired electromagnetic properties by means of pertinent coordinate transformations. In general, such schemes are meant to appropriately tailor the constitutive parameters of metamaterials in order to control the trajectory of light in two and three dimensions. Here we introduce a new class of one-dimensional optical transformations that exploits the mathematical framework of supersymmetry (SUSY). This systematic approach can be utilized to synthesize photonic configurations with identical reflection and transmission characteristics, down to the phase, for all incident angles, thus rendering them perfectly indistinguishable to an external observer. Along these lines, low-contrast dielectric arrangements can be designed to fully mimic the behavior of a given high-contrast structure that would have been otherwise beyond the reach of available materials and existing fabrication techniques. Similar strategies can also be adopted to re...
Characterizing high- n quasi-one-dimensional strontium Rydberg atoms
Hiller, Moritz; Yoshida, Shuhei; Burgdörfer, Joachim; Ye, Shuzhen; Zhang, Xinyue; Dunning, F. Barry
2014-05-01
The production of high- n, n ~ 300 , quasi-one-dimensional strontium Rydberg atoms by two-photon excitation of selected extreme Stark states in the presence of a weak dc field is examined using a crossed laser-atom beam geometry. The polarization of the product states is probed using three independent techniques which are analyzed with the aid of classical-trajectory Monte Carlo simulations that employ initial ensembles based on quantum calculations using a two-active-electron model. Comparisons between theory and experiment demonstrate that the product states have large dipole moments, ~ 1 . 0 - 1 . 2n2 a . u . and that they can be engineered using pulsed electric fields to create a wide variety of target states. Research supported by the NSF, the Robert A Welch Foundation, and the FWF (Austria).
Topologically protected states in one-dimensional systems
Fefferman, C L; Weinstein, M I
2017-01-01
The authors study a class of periodic Schrödinger operators, which in distinguished cases can be proved to have linear band-crossings or "Dirac points". They then show that the introduction of an "edge", via adiabatic modulation of these periodic potentials by a domain wall, results in the bifurcation of spatially localized "edge states". These bound states are associated with the topologically protected zero-energy mode of an asymptotic one-dimensional Dirac operator. The authors' model captures many aspects of the phenomenon of topologically protected edge states for two-dimensional bulk structures such as the honeycomb structure of graphene. The states the authors construct can be realized as highly robust TM-electromagnetic modes for a class of photonic waveguides with a phase-defect.
Few quantum particles on one dimensional lattices
Energy Technology Data Exchange (ETDEWEB)
Valiente Cifuentes, Manuel
2010-06-18
There is currently a great interest in the physics of degenerate quantum gases and low-energy few-body scattering due to the recent experimental advances in manipulation of ultracold atoms by light. In particular, almost perfect periodic potentials, called optical lattices, can be generated. The lattice spacing is fixed by the wavelength of the laser field employed and the angle betwen the pair of laser beams; the lattice depth, defining the magnitude of the different band gaps, is tunable within a large interval of values. This flexibility permits the exploration of different regimes, ranging from the ''free-electron'' picture, modified by the effective mass for shallow optical lattices, to the tight-binding regime of a very deep periodic potential. In the latter case, effective single-band theories, widely used in condensed matter physics, can be implemented with unprecedent accuracy. The tunability of the lattice depth is nowadays complemented by the use of magnetic Feshbach resonances which, at very low temperatures, can vary the relevant atom-atom scattering properties at will. Moreover, optical lattices loaded with gases of effectively reduced dimensionality are experimentally accessible. This is especially important for one spatial dimension, since most of the exactly solvable models in many-body quantum mechanics deal with particles on a line; therefore, experiments with one-dimensional gases serve as a testing ground for many old and new theories which were regarded as purely academic not so long ago. The physics of few quantum particles on a one-dimensional lattice is the topic of this thesis. Most of the results are obtained in the tight-binding approximation, which is amenable to exact numerical or analytical treatment. For the two-body problem, theoretical methods for calculating the stationary scattering and bound states are developed. These are used to obtain, in closed form, the two-particle solutions of both the Hubbard and
Institute of Scientific and Technical Information of China (English)
章海锋; 郑建平; 朱荣军
2012-01-01
The transfer matrix method was applied to study on the properties of tunable prohibited band gaps for one-dimensional ternary magnetized plasma photonic crystals with TE wave arbitrary incident under ideal conditions. TE wave would be divided into left-handed circularly polarized wave and right-handed circularly polarized wave after propagation through one-dimensional ternary magnetized plasma photonic crystals. The calculated transmission coefficients were used to analyze the effects of parameter of plasma, plasma filling factor, incident angle and relative dielectric constant for dielectric layer on the properties of tunable prohibited band gap. The results illustrate that the width of band gaps can not be broadened by increasing plasma collision frequency, the numbers and width of band gaps can be tuned by changing plasma frequency, plasma filling factor and relative dielectric constant for dielectric layer. The band gaps for right-handed circularly polarized wave can be tuned by the plasma gyro frequency, but band gaps for the left-handed circularly polarized wave can't influenced. Low-frequency region of band gaps will be broadened, while high-frequency region of band gaps will be firstly narrow and then broaden with increasing incident angle.%在理想条件下,为了研究等离子体参数、填充率、入射角度和介质层相对介电常数对一维三元磁化等离子体光子晶体的禁带特性的影响,用由传输矩阵法计算得到的TE波任意角度入射时的左旋极化波(LCP)和右旋极化波(RCP)的透射系数来研究其禁带特性.结果表明,仅增加等离子体碰撞频率不能实现禁带宽度的拓展,改变等离子体频率、填充率和介质层的相对介电常数能实现对禁带宽度和数目的调谐.改变等离子体回旋频率能实现对右旋极化波的禁带的调谐,但对左旋极化波的禁带几乎无影响.入射角度的增大使得禁带低频区域带宽变大,而高频区域带宽则是将先减小再增大.
One-Dimensional (1-D) Nanoscale Heterostructures
Institute of Scientific and Technical Information of China (English)
Guozhen SHEN; Di CHEN; Yoshio BANDO; Dmitri GOLBERG
2008-01-01
One-dimensional (1-D) nanostructures have been attracted much attention as a result of their exceptional properties, which are different from bulk materials. Among 1-D nanostructures, 1-D heterostructures with modulated compositions and interfaces have recently become of particular interest with respect to potential applications in nanoscale building blocks of future optoelectronic devices and systems. Many kinds of methods have been developed for the synthesis of 1-D nanoscale heterostructures. This article reviews the most recent development, with an emphasize on our own recent efforts, on 1-D nanoscale heterostructures, especially those synthesized from the vapor deposition methods, in which all the reactive precursors are mixed together in the reaction chamber. Three types of 1-D nanoscale heterostructures, defined from their morphologies characteristics, are discussed in detail, which include 1-D co-axial core-shell heterostructures, 1-D segmented heterostructures and hierarchical heterostructures. This article begins with a brief survey of various methods that have been developed for synthesizing 1-D nanoscale heterostructures and then mainly focuses on the synthesis, structures and properties of the above three types of nanoscale heterostructures. Finally, this review concludes with personal views towards the topic of 1-D nanoscale heterostructures.
One-dimensional nanomaterials: Synthesis and applications
Lei, Bo
My research mainly covers three types of one-dimensional (1D) nanomaterials: metal oxide nanowires, transition metal oxide core-shell nanowires and single-walled carbon nanotubes. This new class of nanomaterials has generated significant impact in multiple fields including electronics, medicine, computing and energy. Their peculiar, fascinating properties are promising for unique applications on electronics, spintronics, optical and chemical/biological sensing. This dissertation will summarize my research work on these three 1D nanomaterials and propose some ideas that may lead to further development. Chapter 1 will give a brief introduction of nanotechnology journey and 1D nanomaterials. Chapter 2 and 3 will discuss indium oxide nanowires, as the representative of metal oxide nanwires. More specifically, chapter 2 is focused on the synthesis, material characterization, transport studies and doping control of indium oxide nanowires; Chapter 3 will give a comprehensive review of our systematic studies on molecular memory applications based on molecule/indium oxide nanowire heterostructures. Chapter 4 will introduce another 1D nanomaterial-transition metal oxide (TMO) core-shell nanowires. The discuss will focus on the synthesis of TMO nanowires, material analysis and their electronic properties as a function of temperature and magnetic field. Chapter 5 is dedicated to aligned single-walled carbon nanotubes (SWNTs) on synthesis with rational control of position and orientation, detailed characterization and construction of scaled top-gated transistors. This chapter presents a way to produce the p- and n-type nanotube transistors based on gate voltage polarity control during electrical breakdown. Finally, chapter 6 summarizes the above discussions and proposes some suggestions for future studies.
MARCUSE’S ONE-DIMENSIONAL SOCIETY IN ONE-DIMENSIONAL MAN
Directory of Open Access Journals (Sweden)
MILOS RASTOVIC
2013-05-01
Full Text Available Nowadays, Marcuse’s main book One-Dimensional Man is almost obsolete, or rather passé. However, there are reasons to renew the reading of his book because of “the crisis of capitalism,” and the prevailing framework of technological domination in “advanced industrial society” in which we live today. “The new forms of control” in “advanced industrial societies” have replaced traditional methods of political and economic administration. The dominant structural element of “advanced industrial society” has become a technical and scientific apparatus of production and distribution of technology and administrative practice based on application of impersonal rules by a hierarchy of associating authorities. Technology has been liberated from the control of particular interests, and it has become the factor of domination in itself. Technological domination stems from the technical development of the productive apparatus that reproduces its ability into all spheres of social life (cultural, political, and economic. Based upon this consideration, in this paper, I will examine Marcuse’s ideas of “the new forms of control,” which creates a one–dimensional society. Marcuse’s fundamental thesis in One-Dimensional Man is that technological rationality is the most dominant factor in an “advanced industrial society,” which unites two earlier opposing forces of dissent: the bourgeoisie and the proletariat.
Ruostekoski, Janne
2016-01-01
We study the transmission of light through a one-dimensional waveguide that confines strongly coupled classical or quantum degenerate fermionic atomic ensembles. The emergence of light-induced correlation effects between the atoms is analyzed by using stochastic Monte-Carlo simulations and transfer matrix methods of transport theory. The conditions of the correlated collective response are identified in terms of the atom density, thermal broadening, and photon losses. We also calculate the "cooperative Lamb shift" for the waveguide transmission resonance, and discuss line shifts that are specific to effectively one-dimensional waveguide systems.
Topological water wave states in a one-dimensional structure
Yang, Zhaoju; Gao, Fei; Zhang, Baile
2016-01-01
Topological concepts have been introduced into electronic, photonic, and phononic systems, but have not been studied in surface-water-wave systems. Here we study a one-dimensional periodic resonant surface-water-wave system and demonstrate its topological transition. By selecting three different water depths, we can construct different types of water waves - shallow, intermediate and deep water waves. The periodic surface-water-wave system consists of an array of cylindrical water tanks connected with narrow water channels. As the width of connecting channel varies, the band diagram undergoes a topological transition which can be further characterized by Zak phase. This topological transition holds true for shallow, intermediate and deep water waves. However, the interface state at the boundary separating two topologically distinct arrays of water tanks can exhibit different bands for shallow, intermediate and deep water waves. Our work studies for the first time topological properties of water wave systems, and paves the way to potential management of water waves. PMID:27373982
Atom-light interactions in quasi-one-dimensional nanostructures: A Green's-function perspective
Asenjo-Garcia, A.; Hood, J. D.; Chang, D. E.; Kimble, H. J.
2017-03-01
Based on a formalism that describes atom-light interactions in terms of the classical electromagnetic Green's function, we study the optical response of atoms and other quantum emitters coupled to one-dimensional photonic structures, such as cavities, waveguides, and photonic crystals. We demonstrate a clear mapping between the transmission spectra and the local Green's function, identifying signatures of dispersive and dissipative interactions between atoms. We also demonstrate the applicability of our analysis to problems involving three-level atoms, such as electromagnetically induced transparency. Finally we examine recent experiments, and anticipate future observations of atom-atom interactions in photonic band gaps.
Gibbs measures and phase transitions in one-dimensional models
Mallak, Saed
2000-01-01
Ankara : Department of Mathematics and the Institute of Engineering and Sciences of Bilkent University, 2000. Thesis (Ph.D.) -- Bilkent University, 2000. Includes bibliographical references leaves 63-64 In this thesis we study the problem of limit Gibbs measures in one-dimensional models. VVe investigate uniqueness conditions for the limit Gibbs measures for one-dimensional models. VVe construct a one-dimensional model disproving a uniqueness conjecture formulated before for...
Glassy behavior in a one-dimensional continuous-wave erbium-doped random fiber laser
Gomes, Anderson S. L.; Lima, Bismarck C.; Pincheira, Pablo I. R.; Moura, André L.; Gagné, Mathieu; Raposo, Ernesto P.; de Araújo, Cid B.; Kashyap, Raman
2016-07-01
The photonic analog of the paramagnetic to spin-glass phase transition in disordered magnetic systems, signaled by the phenomenon of replica symmetry breaking, has been reported using random lasers as the photonic platform. We report here a demonstration of replica symmetry breaking in a one-dimensional photonic system consisting of an erbium-doped random fiber laser operating in the continuous-wave regime. The system is based on a unique random fiber grating system which plays the role of random scattering, providing the disordered feedback mechanism. The clear transition from a photonic paramagnetic to a photonic spin-glass phase, characterized by the Parisi overlap parameter, was verified and indicates the glassy random-fiber-laser behavior.
One dimensional Convolutional Goppa Codes over the projective line
Pérez, J A Domínguez; Sotelo, G Serrano
2011-01-01
We give a general method to construct MDS one-dimensional convolutional codes. Our method generalizes previous constructions of H. Gluesing-Luerssen and B. Langfeld. Moreover we give a classification of one-dimensional Convolutional Goppa Codes and propose a characterization of MDS codes of this type.
One-dimensional diffusion model in an Inhomogeneous region
CSIR Research Space (South Africa)
Fedotov, I
2006-01-01
Full Text Available A one-dimensional model is developed to describe atomic diffusion in a graphite tube atomizer for electrothermal atomic adsorption spectrometry. The underlying idea of the model is the solution of an inhomogeneous one-dimensional diffusion equation...
Properties of a one-dimensional periodicity of the gravitational interaction
Scotognella, F
2016-01-01
We briefly discuss the possibility to describe with a formalism, analogous to the Bragg law and the transfer matrix method used for photonic crystals, the behaviour of the kinetic energy of an object travelling through a one-dimensional (1D) modulation of the gravitational interaction, i.e. a 1D gravitational crystal. We speculate that certain ranges of the kinetic energy of an object with mass m and speed v cannot travel through the crystal, giving rise to a gravitational gap.
Emergence of correlated optics in one-dimensional waveguides for classical and quantum atomic gases
Ruostekoski, Janne; Javanainen, Juha
2016-09-01
We analyze the emergence of correlated optical phenomena in the transmission of light through a waveguide that confines classical or ultracold quantum degenerate atomic ensembles. The conditions of the correlated collective response are identified in terms of atom density, thermal broadening, and photon losses by using stochastic Monte Carlo simulations and transfer matrix methods of transport theory. We also calculate the "cooperative Lamb shift" for the waveguide transmission resonance, and discuss line shifts that are specific to effectively one-dimensional waveguide systems.
Torsional Detwinning Domino in Nanotwinned One-Dimensional Nanostructures.
Zhou, Haofei; Li, Xiaoyan; Wang, Ying; Liu, Zishun; Yang, Wei; Gao, Huajian
2015-09-09
How to maintain sustained deformation in one-dimensional nanostructures without localized failure is an important question for many applications of nanotechnology. Here we report a phenomenon of torsional detwinning domino that leads to giant rotational deformation without localized failure in nanotwinned one-dimensional metallic nanostructures. This mechanism is demonstrated in nanotwinned Cu nanorods via molecular dynamics simulations, where coherent twin boundaries are transformed into twist boundaries and then dissolved one by one, resulting in practically unlimited rotational deformation. This finding represents a fundamental advance in our understanding of deformation mechanisms in one-dimensional metallic nanostructures.
A NEW ONE-DIMENSIONAL CHAOTIC MAP WITH INFINITE COLLAPSES
Institute of Scientific and Technical Information of China (English)
Qiu Yuehong; He Chen; Zhu Hongwen
2002-01-01
This letter presents a new one-dimensional chaotic map with infinite collapses. Theoretical analyses show that the map has complicated dynamical behavior and ideal distribution.The map can be applied in chaotic spreading spectrum communication and chaotic cipher.
One-dimensional spatially dependent solute transport in semi ...
African Journals Online (AJOL)
One-dimensional spatially dependent solute transport in semi-infinite porous media: an analytical solution. ... Journal Home > Vol 9, No 4 (2017) > ... In this mathematical model the dispersion coefficient is considered spatially dependent while ...
One dimensional models of excitons in carbon nanotubes
DEFF Research Database (Denmark)
Cornean, Horia Decebal; Duclos, P.; Pedersen, Thomas Garm
Excitons in carbon nanotubes may be modeled by two oppositely charged particles living on the surface of a cylinder. We derive three one dimensional effective Hamiltonians which become exact as the radius of the cylinder vanishes. Two of them are solvable.......Excitons in carbon nanotubes may be modeled by two oppositely charged particles living on the surface of a cylinder. We derive three one dimensional effective Hamiltonians which become exact as the radius of the cylinder vanishes. Two of them are solvable....
An investigation of dopping profile for a one dimensional heterostructure
Huang, Zhaohui
2005-03-01
A one-dimensional junction is formed by joining two silicon nanowires whose surfaces are terminated with capping groups of different electronegativity and polarizability. If this heterostructure is doped (with e.g. phosphorous) on the side with the higher bandgap, the system becomes a modulation doped heterostructure with novel one-dimensional electrostatics. We use density functional theory calculations in the pseudopotential approximation, plus empirical model calculations, to investigate doping profiles in this new class of nanostructures.
Fidelity of an electron in one-dimensional determined potentials
Institute of Scientific and Technical Information of China (English)
Song Wen-Guang; Tong Pei-Qing
2009-01-01
We numerically study the fidelity of an electron in the one-dimensional Harper model and in the one-dimensional slowly varying potential model. Our results show that many properties of the two models can be well reflected by the fidelity: (i) the mobility edge and metal-insulator transition can be characterized by the static fidelity; (ii) the extended state and localized state can be identified by the dynamic fidelity. Therefore, it may broaden the applied areas of the fidelity.
Institute of Scientific and Technical Information of China (English)
仲义; 许吉; 陆云清; 王敏娟; 王瑾
2014-01-01
柱矢量光束具有柱对称性的偏振分布，其独特的光场分布和聚焦特性被广泛应用于光学微操纵及光学成像等领域，并迅速向亚波长尺度拓展。通常，亚波长尺度聚焦采用等离激元透镜实现，但存在光场调控的偏振态局限性。而借助光子晶体的负折射效应，不仅能够实现亚波长聚焦或成像，而且应对正交偏振态同时有效。采用对电磁波具有更强调控能力的一维金属光子晶体结构，计算得到的能带结构和等频曲线表明其负折射效应在特定波段对正交偏振态同时有效。在此基础上设计出一维金属光子晶体柱对称平凹镜结构，通过有限元算法模拟显示了可见光波段的径向和旋向偏振光的同时亚波长聚焦行为。进一步的结果表明，改变柱矢量光束的偏振组分能够直接有效地调节焦场空间分布及偏振分布特性。所提出的平凹镜结构能够实现对任意偏振组分的柱矢量光束的亚波长尺度聚焦，且该结构的设计对于各波段情况均有参考意义。该研究结果对小尺度粒子的光学微操纵、超分辨率成像等相关领域具有潜在的应用价值。%Cylindrical vector beams (CVB) can exhibit a unique optical field distribution and focusing characteristic, due to the cylindrical symmetry in polarization. They are widely used in optical micro-manipulation, super-resolution imaging etc. and can be extended to subwavelength scale applications rapidly. Usually, the focusing CVB in subwavelength dimensions is realized by using plasmonic lens. However, this method is restricted by the state of polarization of electromagnetic waves. Nevertheless, when the negative refraction effect of photonic crystals is utilized, subwavelength focusing or imaging can be achieved in orthogonal states of polarization simultaneously. In this paper, the one-dimensional metallic photonic crystal (1D-MPC) with stronger manipulation ability is
One dimensional speckle fields generated by three phase level diffusers
Cabezas, L.; Amaya, D.; Bolognini, N.; Lencina, A.
2015-02-01
Speckle patterns have usually been obtained by using ground glass as random diffusers. Liquid-crystal spatial light modulators have opened the possibility of engineering tailored speckle fields obtained from designed diffusers. In this work, one-dimensional Gaussian speckle fields with fully controllable features are generated. By employing a low-cost liquid-crystal spatial light modulator, one-dimensional three phase level diffusers are implemented. These diffusers make it possible to control average intensity distribution and statistical independence among the generated patterns. The average speckle size is governed by an external slit pupil. A theoretical model to describe the generated speckle patterns is developed. Experimental and theoretical results confirming the generation of one-dimensional speckle fields are presented. Some possible applications of these speckles, such as atom trapping and super-resolution imaging, are briefly envisaged.
Analysis of one dimensional and two dimensional fuzzy controllers
Institute of Scientific and Technical Information of China (English)
Ban Xiaojun; Gao Xiaozhi; Huang Xianlin; Wu Tianbao
2006-01-01
The analytical structures and the corresponding mathematical properties of the one dimensional and two dimensional fuzzy controllers are first investigated in detail.The nature of these two kinds of fuzzy controllers is next probed from the perspective of control engineering. For the one dimensional fuzzy controller, it is concluded that this controller is a combination of a saturation element and a nonlinear proportional controller, and the system that employs the one dimensional fuzzy controller is the combination of an open-loop control system and a closedloop control system. For the latter case, it is concluded that it is a hybrid controller, which comprises the saturation part, zero-output part, nonlinear derivative part, nonlinear proportional part, as well as nonlinear proportional-derivative part, and the two dimensional fuzzy controller-based control system is a loop-varying system with varying number of control loops.
A review on one dimensional perovskite nanocrystals for piezoelectric applications
Directory of Open Access Journals (Sweden)
Li-Qian Cheng
2016-03-01
Full Text Available In recent years, one-dimensional piezoelectric nanomaterials have become a research topic of interest because of their special morphology and excellent piezoelectric properties. This article presents a short review on one dimensional perovskite piezoelectric materials in different systems including Pb(Zr,TiO3, BaTiO3 and (K,NaNbO3 (KNN. We emphasize KNN as a promising lead-free piezoelectric compound with a high Curie temperature and high piezoelectric properties and describe its synthesis and characterization. In particular, details are presented for nanoscale piezoelectricity characterization of a single KNN nanocrystal by piezoresponse force microscopy. Finally, this review describes recent progress in applications based on one dimensional piezoelectric nanostructures with a focus on energy harvesting composite materials.
One-dimensional models of excitons in carbon nanotubes
DEFF Research Database (Denmark)
Cornean, Horia Decebal; Duclos, Pierre; Pedersen, Thomas Garm
2004-01-01
Excitons in carbon nanotubes may be modeled by two oppositely charged particles living on the surface of a cylinder. We derive three one-dimensional effective Hamiltonians which become exact as the radius of the cylinder vanishes. Two of them are solvable.......Excitons in carbon nanotubes may be modeled by two oppositely charged particles living on the surface of a cylinder. We derive three one-dimensional effective Hamiltonians which become exact as the radius of the cylinder vanishes. Two of them are solvable....
One-dimensional Nanostructured Materials From Organic Precursor
Institute of Scientific and Technical Information of China (English)
K. F. Cai
2005-01-01
@@ 1Introduction One-dimensional nanostructured materials, such as nanowires, nanobelts, nanotubes and nanocables have been attracting a great research interest in the last decade due to their superior electrical, optical, mechanical and thermal properties, and many methods have been explored to synthesis of the materials, e.g., arc discharge, laser ablation, chemical vapor deposition, thermal evaporation, sol-gel method, template method and so on. In this work, we present a novel and simple method to one-dimensional nanostructured materials by pyrolysis of organic precursor.
Branching solutions to one-dimensional variational problems
Ivanov, A O
2001-01-01
This book deals with the new class of one-dimensional variational problems - the problems with branching solutions. Instead of extreme curves (mappings of a segment to a manifold) we investigate extreme networks, which are mappings of graphs (one-dimensional cell complexes) to a manifold. Various applications of the approach are presented, such as several generalizations of the famous Steiner problem of finding the shortest network spanning given points of the plane. Contents: Preliminary Results; Networks Extremality Criteria; Linear Networks in R N; Extremals of Length Type Functionals: The
Institute of Scientific and Technical Information of China (English)
LANG Jia-Hong
2011-01-01
Single photon transport properties in a one-dimensional array of coupled microcavities waveguide coupled to a whispering-gallery resonator interacting with a A-type system are theoretically investigated.The calculations reveal that the transport properties of single photons with arbitrary energy can be controlled by varying the Rabi frequency and detuning the control optical field.This phenomenon can be used for controllable optical switching.Single photon transport properties in a onedimensional waveguide coupled to a two-level[1-10] or multi-level[11-17] system have been studied theoretically and experimentally for their potential applications in quantum information and all-optical devices.A coupled cavity array is considered as a one-dimensional waveguide and the single photon transport properties in such a system coupled to a two-level and multi-level system have been studied.%Single photon transport properties in a one-dimensional array of coupled microcavities waveguide coupled to a whispering-gallery resonator interacting with a A-type system are theoretically investigated. The calculations reveal that the transport properties of single photons with arbitrary energy can be controlled by varying the Rabi frequency and detuning the control optical field. This phenomenon can be used for controllable optical switching.
Symmetricity of Distribution for One-Dimensional Hadamard Walk
Konno, N; Soshi, T; Konno, Norio; Namiki, Takao; Soshi, Takahiro
2002-01-01
In this paper we study a one-dimensional quantum random walk with the Hadamard transformation which is often called the Hadamard walk. We construct the Hadamard walk using a transition matrix on probability amplitude and give some results on symmetricity of probability distributions for the Hadamard walk.
Time correlation functions for the one-dimensional Lorentz gas
Mazo, R.M.; Beijeren, H. van
1983-01-01
The velocity autocorrelation function and related quantities are investigated for the one-dimensional deterministic Lorentz gas, consisting of randomly distributed fixed scatterers and light particles moving back and forth between two of these at a constant given speed. An expansion for the velocity
Current-Voltage Characteristics of Quasi-One-Dimensional Superconductors
DEFF Research Database (Denmark)
Vodolazov, D.Y.; Peeters, F.M.; Piraux, L.
2003-01-01
The current-voltage (I-V) characteristics of quasi-one-dimensional superconductors were discussed. The I-V characteristics exhibited an unusual S behavior. The dynamics of superconducting condensate and the existence of two different critical currents resulted in such an unusual behavior....
The Long Decay Model of One-Dimensional Projectile Motion
Lattery, Mark Joseph
2008-01-01
This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo ("in De Motu") and by contemporary students. Implications for instruction are…
Quasi-one-dimensional scattering in a discrete model
DEFF Research Database (Denmark)
Valiente, Manuel; Mølmer, Klaus
2011-01-01
that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model...
One-dimensional Bose gas on an atom chip
van Amerongen, A.H.
2008-01-01
We describe experiments investigating the (coherence) properties of a finite-temperature one-dimensional (1D) Bose gas with repulsive interactions. The confining magnetic field is generated with a micro-electronic circuit. This microtrap for atoms or `atom chip' is particularly suited to generate a
Quantum Dynamics of One-Dimensional Nanocrystalline Solids
Institute of Scientific and Technical Information of China (English)
丁建文; 颜晓红; 曹觉先; 王登龙
2002-01-01
A novel ballistic-nonballistic dynamic transition in one-dimensional nanocrystalline solids is found upon varyingthe strength of the composition modulation and the grain-boundary effect. This can contribute to the under-standing of the strange electronic transport properties of nanostructured systems.
One-dimensional models of thermal activation under shear stress
CSIR Research Space (South Africa)
Nabarro, FRN
2003-01-01
Full Text Available The analysis of thermal activation under shear stress in three- and even two-dimensional models presents unresolved problems. The analysis of one-dimensional models presented here may illuminate the study of more realistic models. For the model...
How good are one-dimensional Josephson junction models?
DEFF Research Database (Denmark)
Lomdahl, P. S.; Olsen, O.H.; Eilbeck, J. C.
1985-01-01
A two-dimensional model of Josephson junctions of overlap type is presented and shown to reduce to the usual one-dimensional (1D) model in the limit of a very narrow junction. Comparisons between the stability limits for fluxon reflection obtained from the two models suggest that the many results...
Quasi-one-dimensional intermittent flux behavior in superconducting films
DEFF Research Database (Denmark)
Qviller, A. J.; Yurchenko, V. V.; Galperin, Y. M.
2012-01-01
. The intermittent behavior shows no threshold value in the applied field, in contrast to conventional flux jumping. The results strongly suggest that the quasi-one-dimensional flux jumps are of a different nature than the thermomagnetic dendritic (branching) avalanches that are commonly found in superconducting...
Radiative decay of the one-dimensional large acoustic polaron
Energy Technology Data Exchange (ETDEWEB)
Ivic, Zoran; Zekovic, Slobodan; Przulj, Zeljko
2002-12-30
Finite temperature dynamics and stability of the adiabatic large acoustic polaron in one-dimensional systems have been examined by means of the perturbation method based upon the inverse scattering transform. Polaron life-time was estimated in dependence of temperature and electron (exciton)-phonon coupling constant.
An algebraic study of unitary one dimensional quantum cellular automata
Arrighi, P
2005-01-01
We provide algebraic characterizations of unitary one dimensional quantum cellular automata. We do so both by algebraizing existing decision procedures, and by adding constraints into the model which do not change the quantum cellular automata's computational power. The configurations we consider have finite but unbounded size.
Novel Progress in One-Dimensional Carbon Nanotubes Studies
Institute of Scientific and Technical Information of China (English)
无
2004-01-01
@@ One-dimensional carbon nanotubes (CNT) have received considerable attention from researchers worldwide. It is not only because of their unique physical properties, but also their potential applications. Recently, researchers of the CAS Institute of Physics have made new progress in the field.
Quantum transport in strongly interacting one-dimensional nanostructures
Agundez, R. R.
2015-01-01
In this thesis we study quantum transport in several one-dimensional systems with strong electronic interactions. The first chapter contains an introduction to the concepts treated throughout this thesis, such as the Aharonov-Bohm effect, the Kondo effect, the Fano effect and quantum state transfer.
Bloch oscillations in an aperiodic one-dimensional potential
de Moura, FABF; Lyra, ML; Dominguez-Adame, F; Malyshev, V.A.
2005-01-01
We study the dynamics of an electron subjected to a static uniform electric field within a one-dimensional tight-binding model with a slowly varying aperiodic potential. The unbiased model is known to support phases of localized and extended one-electron states separated by two mobility edges. We sh
Lie symmetry algebra of one-dimensional nonconservative dynamical systems
Institute of Scientific and Technical Information of China (English)
Liu Cui-Mei; Wu Run-Heng; Fu Jing-Li
2007-01-01
Lie symmetry algebra of linear nonconservative dynamical systems is studied in this paper. By using 1-1 mapping,the Lie point and Lie contact symmetry algebras are obtained from two independent solutions of the one-dimensional linear equations of motion.
Intertwining technique for the one-dimensional stationary Dirac equation
Nieto, L M; Samsonov, B F; Samsonov, Boris F.
2003-01-01
The technique of differential intertwining operators (or Darboux transformation operators) is systematically applied to the one-dimensional Dirac equation. The following aspects are investigated: factorization of a polynomial of Dirac Hamiltonians, quadratic supersymmetry, closed extension of transformation operators, chains of transformations, and finally particular cases of pseudoscalar and scalar potentials. The method is widely illustrated by numerous examples.
One Dimensional Quasi-Exactly Solvable Differential Equations
Fasihi, Mohammad A.
2006-01-01
In this paper by means of similarity transformation we find some one-dimensional quasi-exactly solvable differential equations and their related Hamiltonians which appear in physical problems. We have provided also two examples with application of these differential equations.
Quantum dynamics of one-dimensional nanocrystalline solids
Ding Jian Wen; Cao Jue Xian; Wang Deng Long
2002-01-01
A novel ballistic-non-ballistic dynamic transition in one-dimensional nanocrystalline solids is found upon varying the strength of the composition modulation and the grain-boundary effect. This can contribute to the understanding of the strange electronic transport properties of nano-structured systems
Exact results for one dimensional fluids through functional integration
Fantoni, Riccardo
2016-01-01
We review some of the exactly solvable one dimensional continuum fluid models of equilibrium classical statistical mechanics under the unified setting of functional integration in one dimension. We make some further developments and remarks concerning fluids with penetrable particles. We then apply our developments to the study of the Gaussian core model for which we are unable to find a well defined thermodynamics.
Transport through a Finite One-Dimensional Crystal
Kouwenhoven, L.P.; Hekking, F.W.J.; Wees, B.J. van; Harmans, C.J.P.M.; Timmering, C.E.; Foxon, C.T.
1990-01-01
We have studied the magnetotransport properties of an artificial one-dimensional crystal. The crystal consists of a sequence of fifteen quantum dots, defined in the two-dimensional electron gas of a GaAs/AlGaAs heterostructure by means of a split-gate technique. At a fixed magnetic field of 2 T, two
Direct Current Hopping Conductivity in One-Dimensional Nanometre Systems
Institute of Scientific and Technical Information of China (English)
宋祎璞; 徐慧; 罗峰
2003-01-01
A one-dimensional random nanocrystalline chain model is established. A dc electron-phonon-field conductance model of electron tunnelling transfer is set up, and a new dc conductance formula in one-dimensional nanometre systems is derived. By calculating the dc conductivity, the relationship among the electric field, temperature and conductivity is analysed, and the effect of the crystalline grain size and the distortion of interfacial atoms on the dc conductance is discussed. The result shows that the nanometre system appears the characteristic of negative differential dependence of resistance and temperature at low temperature. The dc conductivity of nanometre systems varies with the change of electric field and trends to rise as the crystalline grain size increases and to decrease as the distorted degree of interfacial atoms increases.
True Bilayer Exciton Condensate of One-Dimensional Electrons
Kantian, A.; Abergel, D. S. L.
2017-07-01
We theoretically predict that a true bilayer exciton condensate, characterized by off-diagonal long-range order and global phase coherence, can be created in one-dimensional solid state electron systems. The mechanism by which this happens is to introduce a single particle hybridization of electron and hole populations, which locks the phase of the relevant mode and hence invalidates the Mermin-Wagner theorem. Electron-hole interactions then amplify this tendency towards off-diagonal long-range order, enhancing the condensate properties by more than an order of magnitude over the noninteracting limit. We show that the temperatures below which a substantial condensate fraction would form could reach hundreds of Kelvin, a benefit of the weak screening in one-dimensional systems.
Fate of classical solitons in one-dimensional quantum systems.
Energy Technology Data Exchange (ETDEWEB)
Pustilnik, M.; Matveev, K. A.
2015-11-23
We study one-dimensional quantum systems near the classical limit described by the Korteweg-de Vries (KdV) equation. The excitations near this limit are the well-known solitons and phonons. The classical description breaks down at long wavelengths, where quantum effects become dominant. Focusing on the spectra of the elementary excitations, we describe analytically the entire classical-to-quantum crossover. We show that the ultimate quantum fate of the classical KdV excitations is to become fermionic quasiparticles and quasiholes. We discuss in detail two exactly solvable models exhibiting such crossover, the Lieb-Liniger model of bosons with weak contact repulsion and the quantum Toda model, and argue that the results obtained for these models are universally applicable to all quantum one-dimensional systems with a well-defined classical limit described by the KdV equation.
Resonance Raman spectroscopy in one-dimensional carbon materials
Directory of Open Access Journals (Sweden)
Dresselhaus Mildred S.
2006-01-01
Full Text Available Brazil has played an important role in the development and use of resonance Raman spectroscopy as a powerful characterization tool for materials science. Here we present a short history of Raman scattering research in Brazil, highlighting the important contributions to the field coming from Brazilian researchers in the past. Next we discuss recent and important contributions where Brazil has become a worldwide leader, that is on the physics of quasi-one dimensional carbon nanotubes. We conclude this article by presenting results from a very recent resonance Raman study of exciting new materials, that are strictly one-dimensional carbon chains formed by the heat treatment of very pure double-wall carbon nanotube samples.
One-dimensional XY model: Ergodic properties and hydrodynamic limit
Shuhov, A. G.; Suhov, Yu. M.
1986-11-01
We prove theorems on convergence to a stationary state in the course of time for the one-dimensional XY model and its generalizations. The key point is the well-known Jordan-Wigner transformation, which maps the XY dynamics onto a group of Bogoliubov transformations on the CAR C *-algebra over Z 1. The role of stationary states for Bogoliubov transformations is played by quasifree states and for the XY model by their inverse images with respect to the Jordan-Wigner transformation. The hydrodynamic limit for the one-dimensional XY model is also considered. By using the Jordan-Wigner transformation one reduces the problem to that of constructing the hydrodynamic limit for the group of Bogoliubov transformations. As a result, we obtain an independent motion of "normal modes," which is described by a hyperbolic linear differential equation of second order. For the XX model this equation reduces to a first-order transfer equation.
One-dimensional Si nanolines in hydrogenated Si(001)
François, Bianco; Köster, Sigrun A.; Owen, James G. H.; Renner, Christoph; Bowler, David R.
2012-02-01
We present a detailed study of the structural and electronic properties of a self-assembled silicon nanoline embedded in the H-terminated silicon (001) surface, known as the Haiku stripe. The nanoline is a perfectly straight and defect free endotaxial structure of huge aspect ratio; it can grow micrometre long at a constant width of exactly four Si dimers (1.54 nm). Another remarkable property is its capacity to be exposed to air without suffering any degradation. The nanoline grows independently of any step edges at tunable densities, from isolated nanolines to a dense array of nanolines. In addition to these unique structural characteristics, scanning tunnelling microscopy and density functional theory reveal a one-dimensional state confined along the Haiku core. This nanoline is a promising candidate for the long sought after electronic solid-state one-dimensional model system to explore the fascinating quantum properties emerging in such reduced dimensionality. Phys. Rev. B, 84, 035328 (2011)
Luttinger parameter of quasi-one-dimensional para -H2
Ferré, G.; Gordillo, M. C.; Boronat, J.
2017-02-01
We have studied the ground-state properties of para-hydrogen in one dimension and in quasi-one-dimensional configurations using the path-integral ground-state Monte Carlo method. This method produces zero-temperature exact results for a given interaction and geometry. The quasi-one-dimensional setup has been implemented in two forms: the inner channel inside a carbon nanotube coated with H2 and a harmonic confinement of variable strength. Our main result is the dependence of the Luttinger parameter on the density within the stable regime. Going from one dimension to quasi-one dimension, keeping the linear density constant, produces a systematic increase of the Luttinger parameter. This increase is, however, not enough to reach the superfluid regime and the system always remain in the quasicrystal regime, according to Luttinger liquid theory.
Kinetic properties of small one-dimensional Ising magnetic
Udodov, Vladimir; Spirin, Dmitriy; Katanov Khakas State University Team
2011-03-01
Within the framework of a generalized Ising model, a one-dimensional magnetic of a finite length with free ends is considered. The correlation length critical exponent ν and kinetic critical exponent z of the magnet is calculated taking into account the next nearest neighbor interactions and the external field. Of special interest are non-equilibrium processes taking place within the critical temperature interval, which are characterized critical exponent y and dynamic critical index z . Due to significant difficulties encountered in the experimental investigations (e.g., measurement of z) , a natural solution to this complex problem would be modeling of those non-eqilibrium processes. This work addresses non-equilibrium processes in one-dimensional magnetics. Using the Monte Carlo method, an equilibrium critical exponent of the correlation length ν and the dynamic critical index z are calculated for a finite-size magnetic.
Dark Matter in a One-dimensional Universe
Sigismondi, C
2003-01-01
A computer code to simulate temporal evolution of overdensities in a one-dimensional Universe is presented for didactic purposes. The formation of large scale structures in this one-dimensional universe can be studied both in matter or radiation dominated eras. Since large scale structures are already observed at z > 7, primordial dark matter overdensities delta_DM which are 90 times larger than the observed barionic delta_B in the cosmic microwave background are required at z~1000. This makes possible non-linear gravitational collapse at redshift z >7 and the formation of the structures. Primordial perturbations delta_B~10^-5 do not leave the linear regime of growth without the aid of dark matter's potential wells. This code is suitable for commercial worksheets like MSExcel, StarOffice, or OpenOffice.
Bose gases in one-dimensional harmonic trap
Indian Academy of Sciences (India)
JI-XUAN HOU; JING YANG
2016-10-01
Thermodynamic quantities, occupation numbers and their fluctuations of a one-dimensional Bose gas confined by a harmonic potential are studied using different ensemble approaches. Combining number theory methods, a new approach is presented to calculate the occupation numbers of different energy levels in microcanonical ensemble. The visible difference of the ground state occupation number in grand-canonical ensemble and microcanonical ensemble is found to decrease by power law as the number of particles increases.
Nonequilibrium statistical mechanics in one-dimensional bose gases
Baldovin, F.; Cappellaro, A.; Orlandini, E.; Salasnich, L.
2016-06-01
We study cold dilute gases made of bosonic atoms, showing that in the mean-field one-dimensional regime they support stable out-of-equilibrium states. Starting from the 3D Boltzmann-Vlasov equation with contact interaction, we derive an effective 1D Landau-Vlasov equation under the condition of a strong transverse harmonic confinement. We investigate the existence of out-of-equilibrium states, obtaining stability criteria similar to those of classical plasmas.
ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES
Nikola Stefanović
2007-01-01
In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic ...
Butz, Susanne
2014-01-01
This thesis presents a novel approach to the experimental realization of tunable, superconducting metamaterials. Therefore, conventional resonant meta-atoms are replaced by meta-atoms that contain Josephson junctions, which renders their resonance frequency tunable by an external magnetic field. This tunability is theoretically and experimentally investigated in one-dimensional magnetic and electric metamaterials. For the magnetic metamaterial, the effective, magnetic permeability is determined.
Few interacting fermions in one-dimensional harmonic trap
Sowiński, Tomasz; Dutta, Omjyoti; Lewenstein, Maciej
2013-01-01
We study spin-1/2 fermions, interacting via a two-body contact potential, in a one-dimensional harmonic trap. Applying exact diagonalization, we investigate the behavior at finite interaction strength, and discuss the role of a ground state degeneracy which occurs for sufficiently strong repulsive interaction. Even low temperature or a completely depolarizing channel may then dramatically influence the system's behavior. We calculate level occupation numbers as signatures of thermalization, and we discuss the mechanisms to break the degeneracy.
Hidden Symmetry from Supersymmetry in One-Dimensional Quantum Mechanics
Directory of Open Access Journals (Sweden)
Alexander A. Andrianov
2009-06-01
Full Text Available When several inequivalent supercharges form a closed superalgebra in Quantum Mechanics it entails the appearance of hidden symmetries of a Super-Hamiltonian. We examine this problem in one-dimensional QM for the case of periodic potentials and potentials with finite number of bound states. After the survey of the results existing in the subject the algebraic and analytic properties of hidden-symmetry differential operators are rigorously elaborated in the Theorems and illuminated by several examples.
Thermal breakage of a discrete one-dimensional string.
Lee, Chiu Fan
2009-09-01
We study the thermal breakage of a discrete one-dimensional string, with open and fixed ends, in the heavily damped regime. Basing our analysis on the multidimensional Kramers escape theory, we are able to make analytical predictions on the mean breakage rate and on the breakage propensity with respect to the breakage location on the string. We then support our predictions with numerical simulations.
PT-invariant one-dimensional Coulomb problem
Sinha, A K; Sinha, Anjana; Roychoudhury, Rajkumar
2002-01-01
The one-dimensional Coulomb-like potential with a real coupling constant beta, and a centrifugal-like core of strength G = alpha^2 - {1/4}, viz. V(x) = {alpha^2 - (1/4)}/{(x-ic)^2} + beta/|x-ic|, is discussed in the framework of PT-symmetry. The PT-invariant exactly solvable model so formed, is found to admit a double set of real and discrete energies, numbered by a quasi-parity q = +/- 1.
Impurity modes in the one-dimensional XXZ Heisenberg model
Energy Technology Data Exchange (ETDEWEB)
Sousa, J.M. [Departamento de Física, Universidade Federal do Piauí, Campus Ministro Petrônio Portella, 57072-970 Teresina, Piauí (Brazil); Leite, R.V. [Centro de Ciências Exatas e Tecnologia, Curso de Física, Universidade Estadual Vale do Acaraú, Av. Dr. Guarany 317, Campus Cidao, 62040-730 Sobral, Ceará (Brazil); Landim, R.R. [Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-760 Fortaleza, Ceará (Brazil); Costa Filho, R.N., E-mail: rai@fisica.ufc.br [Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-760 Fortaleza, Ceará (Brazil)
2014-04-01
A Green's function formalism is used to calculate the energy of impurity modes associated with one and/or two magnetic impurities in the one-dimensional Heisenberg XXZ magnetic chain. The system can be tuned from the Heisenberg to the Ising model varying a parameter λ. A numerical study is performed showing two types of localized modes (s and p). The modes depend on λ and the degeneracy of the acoustic modes is broken.
Universal correlations of one-dimensional electrons at low density
Göhmann, F.
2000-01-01
We summarize results on the asymptotics of the two-particle Green functions of interacting electrons in one dimension. Below a critical value of the chemical potential the Fermi surface vanishes, and the system can no longer be described as a Luttinger liquid. Instead, the non-relativistic Fermi gas with infinite point-like repulsion becomes the universal model for the long-wavelength, low temperature physics of the one-dimensional electrons. This model, which we call the impenetrable electro...
PERIODIC SOLUTIONS IN ONE-DIMENSIONAL COUPLED MAP LATTICES
Institute of Scientific and Technical Information of China (English)
郑永爱; 刘曾荣
2003-01-01
It is proven that the existence of nonlinear solutions with time period in one-dimensional coupled map lattice with nearest neighbor coupling. This is a class of systemswhose behavior can be regarded as infinite array of coupled oscillators. A method forestimating the critical coupling strength below which these solutions with time period persistis given. For some particular nonlinear solutions with time period, exponential decay inspace is proved.
One-dimensional contact process: duality and renormalization.
Hooyberghs, J; Vanderzande, C
2001-04-01
We study the one-dimensional contact process in its quantum version using a recently proposed real-space renormalization technique for stochastic many-particle systems. Exploiting the duality and other properties of the model, we can apply the method for cells with up to 37 sites. After suitable extrapolation, we obtain exponent estimates that are comparable in accuracy with the best known in the literature.
Correlation functions of one-dimensional bosons at low temperature
Energy Technology Data Exchange (ETDEWEB)
Kozlowski, K.K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Maillet, J.M. [CNRS, ENS Lyon (France). Lab. de Physique; Slavnov, N.A. [Steklov Mathematical Institute, Moscow (Russian Federation)
2010-12-15
We consider the low-temperature limit of the long-distance asymptotic behavior of the finite temperature density-density correlation function in the one-dimensional Bose gas derived recently in the algebraic Bethe Ansatz framework. Our results confirm the predictions based on the Luttinger liquid and conformal field theory approaches. We also demonstrate that the amplitudes arising in this asymptotic expansion at low-temperature coincide with the amplitudes associated with the so-called critical form factors. (orig.)
Fast Integration of One-Dimensional Boundary Value Problems
Campos, Rafael G.; Ruiz, Rafael García
2013-11-01
Two-point nonlinear boundary value problems (BVPs) in both unbounded and bounded domains are solved in this paper using fast numerical antiderivatives and derivatives of functions of L2(-∞, ∞). This differintegral scheme uses a new algorithm to compute the Fourier transform. As examples we solve a fourth-order two-point boundary value problem (BVP) and compute the shape of the soliton solutions of a one-dimensional generalized Korteweg-de Vries (KdV) equation.
The one-dimensional extended Bose-Hubbard model
Indian Academy of Sciences (India)
Ramesh V Pai; Rahul Pandit
2003-10-01
We use the finite-size, density-matrix-renormalization-group (DMRG) method to obtain the zero-temperature phase diagram of the one-dimensional, extended Bose-Hubbard model, for mean boson density ρ = 1, in the - plane ( and are respectively, onsite and nearest-neighbour repulsive interactions between bosons). The phase diagram includes superfluid (SF), bosonic-Mott-insulator (MI), and mass-density-wave (MDW) phases. We determine the natures of the quantum phase transitions between these phases.
Statistics of resonances in one-dimensional continuous systems
Indian Academy of Sciences (India)
Joshua Feinberg
2009-09-01
We study the average density of resonances (DOR) of a disordered one-dimensional continuous open system. The disordered system is semi-infinite, with white-noise random potential, and it is coupled to the external world by a semi-infinite continuous perfect lead. Our main result is an integral representation for the DOR which involves the probability density function of the logarithmic derivative of the wave function at the contact point.
Exchange effects in a quasi-one-dimensional electron gas
Gold, A.; Ghazali, A.
1990-04-01
We calculate the electron exchange of a quasi-one-dimensional electron gas in a quantum-well wire of radius R0. A two-subband model is considered and the exchange self-energy for the first and second subband is calculated under the assumption that only the lowest subband is partially filled with electrons. Band-bending effects are also discussed. Results for the total energy per electron including kinetic and exchange energy are presented.
Morphology-Controlled Growth of AIN One-Dimensional Nanostructures
Institute of Scientific and Technical Information of China (English)
Ting XIE; Min YE; Xiaosheng FANG; Zhi JIANG; Li CHEN; Mingguang KONG; Yucheng WU; Lide ZHANG
2008-01-01
Aluminum nitride (AIN) nanowires, serrated nanoribbons, and nanoribbons were selectively obtained through a simple chloride assisted chemical vapor deposition process. The morphologies of the products could be controlled by adjusting the deposition position and the flux of the reactant gas. The morphologies and structures of the AIN products were investigated in detail. The formation mechanism of the as-prepared different morphologies of AIN one-dimensional (1D) nanostructures was discussed on the basis of the experimental results.
Analysis of necking based on a one-dimensional model
Audoly, Basile; Hutchinson, John W.
2016-12-01
Dimensional reduction is applied to derive a one-dimensional energy functional governing tensile necking localization in a family of initially uniform prismatic solids, including as particular cases rectilinear blocks in plane strain and cylindrical bars undergoing axisymmetric deformations. The energy functional depends on both the axial stretch and its gradient. The coefficient of the gradient term is derived in an exact and general form. The one-dimensional model is used to analyze necking localization for nonlinear elastic materials that experience a maximum load under tensile loading, and for a class of nonlinear materials that mimic elastic-plastic materials by displaying a linear incremental response when stretch switches from increasing to decreasing. Bifurcation predictions for the onset of necking from the simplified theory compared with exact results suggest the approach is highly accurate at least when the departures from uniformity are not too large. Post-bifurcation behavior is analyzed to the point where the neck is fully developed and localized to a region on the order of the thickness of the block or bar. Applications to the nonlinear elastic and elastic-plastic materials reveal the highly unstable nature of necking for the former and the stable behavior for the latter, except for geometries where the length of the block or bar is very large compared to its thickness. A formula for the effective stress reduction at the center of a neck is established based on the one-dimensional model, which is similar to that suggested by Bridgman (1952).
Gravitational anomalies and one-dimensional behavior of black holes
Energy Technology Data Exchange (ETDEWEB)
Majhi, Bibhas Ranjan, E-mail: bibhas.majhi@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam (India)
2015-12-08
It has been pointed out by Bekenstein and Mayo that the behavior of the black hole’s entropy or information flow is similar to information flow through one-dimensional channel. Here I analyze the same issue with the use of gravitational anomalies. The rate of the entropy change (S{sup .}) and the power (P) of the Hawking emission are calculated from the relevant components of the anomalous stress tensor under the Unruh vacuum condition. I show that the dependence of S{sup .} on the power is S{sup .} ∝P{sup 1/2}, which is identical to that for the information flow in a one-dimensional system. This is established by using the (1+1)-dimensional gravitational anomalies first. Then the fact is further bolstered by considering the (1+3)-dimensional gravitational anomalies. It is found that, in the former case, the proportionality constant is exactly identical to the one-dimensional situation, known as Pendry’s formula, while in the latter situation its value decreases.
Gravitational anomalies and one-dimensional behavior of black holes
Energy Technology Data Exchange (ETDEWEB)
Majhi, Bibhas Ranjan [Indian Institute of Technology Guwahati, Department of Physics, Guwahati, Assam (India)
2015-12-15
It has been pointed out by Bekenstein and Mayo that the behavior of the black hole's entropy or information flow is similar to information flow through one-dimensional channel. Here I analyze the same issue with the use of gravitational anomalies. The rate of the entropy change (S) and the power (P) of the Hawking emission are calculated from the relevant components of the anomalous stress tensor under the Unruh vacuum condition. I show that the dependence of S on the power is S ∝ P{sup 1/2}, which is identical to that for the information flow in a one-dimensional system. This is established by using the (1+1)-dimensional gravitational anomalies first. Then the fact is further bolstered by considering the (1+3)-dimensional gravitational anomalies. It is found that, in the former case, the proportionality constant is exactly identical to the one-dimensional situation, known as Pendry's formula, while in the latter situation its value decreases. (orig.)
Gravitational anomalies and one dimensional behaviour of black holes
Majhi, Bibhas Ranjan
2015-01-01
It has been pointed out by Bekenstein and Mayo that the behavior of the Black hole's entropy or information flow is similar to that through one-dimensional channel. Here I analyse the same issue with the use of gravitational anomalies. The rate of the entropy change ($\\dot{S}$) and the power ($P$) of the Hawking emission are calculated from the relevant components of the anomalous stress-tensor under the Unruh vacuum condition. I show that the dependence of $\\dot{S}$ on power is $\\dot{S}\\propto P^{1/2}$ which is identical to that for the information flow in one dimensional system. This is established by using the ($1+1$) dimensional gravitational anomalies first. Then the fact is further bolstered by considering the ($1+3$) dimensional gravitational anomalies. It is found that in the former case, the proportionality constant is exactly identical to one dimensional situation, known as Pendry's formula, while in later situation its value decreases.
Quasi-one-dimensional scattering in a discrete model
Energy Technology Data Exchange (ETDEWEB)
Valiente, Manuel; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)
2011-11-15
We study quasi-one-dimensional scattering of one and two particles with short-range interactions on a discrete lattice model in two dimensions. One of the directions is tightly confined by an arbitrary trapping potential. We obtain the collisional properties of these systems both at finite and zero Bloch quasimomenta, considering as well finite sizes and transversal traps that support a continuum of states. This is made straightforward by using the exact ansatz for the quasi-one-dimensional states from the beginning. In the more interesting case of genuine two-particle scattering, we find that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model that includes only the effect of the dominant, broadest resonance, which amounts to a single-pole approximation for the interaction coupling constant.
Experimental simulation of two interacting particles in a one-dimensional lattice
Mukherjee, Sebabrata; Goldman, Nathan; Spracklen, Alexander; Andersson, Erika; Öhberg, Patrik; Thomson, Robert R
2016-01-01
We report on the experimental realization of a photonic system that simulates the dynamics of two interacting quantum particles in a one-dimensional lattice. This analogy is realized by means of two-dimensional arrays of coupled optical waveguides, fabricated using femtosecond laser inscription. By tuning the analogous "interaction strength", we reach the strongly-interacting regime of the Hubbard Hamiltonian. In this regime, the formation of bound states is identified through the direct observation of pair tunneling. This effect is emphasized through the suppression of standard tunneling for individual "particles". We then demonstrate the coherent destruction of tunneling (CDT) for the paired particles in the presence of an engineered oscillating force of high frequency. The precise control over the analogous "interaction strength" and driving force offered by our experimental system opens an exciting route towards quantum simulation of few-body physics in photonics.
Validity of One-Dimensional QED for a System with Spatial Symmetry
Lv, Q Z; Su, Q; Grobe, R
2015-01-01
We examine the accuracy of an intrinsically one-dimensional quantum electrodynamics to predict accurately the forces and charges of a three-dimensional system that has a high degree of symmetry and therefore depends effectively only on a single coordinate. As a test case we analyze two charged capacitor plates that are infinitely extended along two coordinate directions. Using the lowest-order fine structure correction to the photon propagator we compute the vacuum's induced charge polarization density and show that the force between the charged plates is increased. Although a one-dimensional theory cannot take the transverse character of the virtual (force-mediating) photons into account, nevertheless it predicts, in lowest order of the fine-structure constant, the Coulomb force law between the plates correctly. However, the quantum correction to the classical result is slightly different between the 1d and 3d theories with the polarization charge density induced from the vacuum underestimated by the 1d appr...
One-dimensional Transport Simulation of Pollutants in Natural Streams
Directory of Open Access Journals (Sweden)
Mostafa Ramezani
2016-10-01
Full Text Available Rivers are the main sources of freshwater systems which governments need to manage and plan to maintain them as per an acceptable quality. In this research, a numerical scheme was used and implemented in MATLAB to provide a one-dimensional water quality tool. This code then was tested with two datasets of Chattahoochee and Mackinaw rivers. To evaluate the model performance, results and sampled data were checked in terms of conformity by using three metrics: CE, MARE, and RMSE. Results were almost near to observed data and metrics’ values were found satisfactory, showing that the employed numerical approach is an appropriate method for surface water quality planning and management.
Universality of anomalous one-dimensional heat conductivity
Lepri, Stefano; Livi, Roberto; Politi, Antonio
2003-12-01
In one and two dimensions, transport coefficients may diverge in the thermodynamic limit due to long-time correlation of the corresponding currents. The effective asymptotic behavior is addressed with reference to the problem of heat transport in one-dimensional crystals, modeled by chains of classical nonlinear oscillators. Extensive accurate equilibrium and nonequilibrium numerical simulations confirm that the finite-size thermal conductivity diverges with system size L as κ∝Lα. However, the exponent α deviates systematically from the theoretical prediction α=1/3 proposed in a recent paper [O. Narayan and S. Ramaswamy, Phys. Rev. Lett. 89, 200601 (2002)].
One-dimensional hydrodynamic model generating turbulent cascade
Matsumoto, Takeshi
2016-01-01
As a minimal mathematical model generating cascade analogous to that of the Navier-Stokes turbulence in the inertial range, we propose a one-dimensional partial-differential-equation model that conserves the integral of the squared vorticity analogue (enstrophy) in the inviscid case. With a large-scale forcing and small viscosity, we find numerically that the model exhibits the enstrophy cascade, the broad energy spectrum with a sizable correction to the dimensional-analysis prediction, peculiar intermittency and self-similarity in the dynamical system structure.
On Global One-Dimensionality proposal in Quantum General Relativity
Glinka, L A
2008-01-01
Quantum General Relativity, better known as Quantum Gravity with additional epithets, currently is faraway from phenomenology. This mental crisis leads at most to empty hypotheses, but not to realistic physics. However, there exists the way, investigated by Dirac, which is constructive for experimental data predictions in astrophysics, high energy physics, and condensed matter physics. It is Field Theory. This article presents certain proposal for new discussion. General Relativity in 3+1 metric field gauge and its canonical quantization is developed. Reduction of the quantum geometrodynamics to Global One-Dimensional bosonic field theory, its quantization, and some conclusions are presented.
Exactly integrable analogue of a one-dimensional gravitating system
Energy Technology Data Exchange (ETDEWEB)
Miller, Bruce N. [Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States)]. E-mail: b.miller@tcu.edu; Yawn, Kenneth R. [Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Maier, Bill [Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States)
2005-10-10
Exchange symmetry in acceleration partitions the configuration space of an N particle one-dimensional gravitational system (OGS) into N{exclamation_point} equivalent cells. We take advantage of the resulting small angular separation between the forces in neighboring cells to construct a related integrable version of the system that takes the form of a central force problem in N-1 dimensions. The properties of the latter, including the construction of trajectories and possible continuum limits, are developed. Dynamical simulation is employed to compare the two models. For some initial conditions, excellent agreement is observed.
One-dimensional inverse problems of mathematical physics
Lavrent'ev, M M; Yakhno, V G; Schulenberger, J R
1986-01-01
This monograph deals with the inverse problems of determining a variable coefficient and right side for hyperbolic and parabolic equations on the basis of known solutions at fixed points of space for all times. The problems are one-dimensional in nature since the desired coefficient of the equation is a function of only one coordinate, while the desired right side is a function only of time. The authors use methods based on the spectral theory of ordinary differential operators of second order and also methods which make it possible to reduce the investigation of the inverse problems to the in
Solution of One-dimensional Dirac Equation via Poincare Map
Bahlouli, Hocine; Jellal, Ahmed
2011-01-01
We solve the general one-dimensional Dirac equation using a "Poincare Map" approach which avoids any approximation to the spacial derivatives and reduces the problem to a simple recursive relation which is very practical from the numerical implementation point of view. To test the efficiency and rapid convergence of this approach we apply it to a vector coupling Woods--Saxon potential, which is exactly solvable. Comparison with available analytical results is impressive and hence validates the accuracy and efficiency of this method.
Fluctuation dissipation ratio in the one dimensional kinetic Ising model
Lippiello, E.; Zannetti, M.
2000-01-01
The exact relation between the response function $R(t,t^{\\prime})$ and the two time correlation function $C(t,t^{\\prime})$ is derived analytically in the one dimensional kinetic Ising model subjected to a temperature quench. The fluctuation dissipation ratio $X(t,t^{\\prime})$ is found to depend on time through $C(t,t^{\\prime})$ in the time region where scaling $C(t,t^{\\prime}) = f(t/t^{\\prime})$ holds. The crossover from the nontrivial form $X(C(t,t^{\\prime}))$ to $X(t,t^{\\prime}) \\equiv 1$ t...
Enhanced dipolar transport in one-dimensional waveguide arrays
Cantillano, Camilo; Real, Bastián; Rojas-Rojas, Santiago; Delgado, Aldo; Szameit, Alexander; Vicencio, Rodrigo A
2016-01-01
We study the transport properties of fundamental and dipolar (first-excited) modes on one-dimensional coupled waveguide arrays. By modulating an optical beam, we are able to generate fundamental and dipolar modes to study discrete diffraction (single-site excitation) and gaussian beam propagation (multi-site excitation \\& phase gradient). We find that dipolar modes experience a coupling constant more than two times larger than the one for fundamental modes. This implies an enhanced transport of energy for dipoles in a tight-binding lattice. Additionally, we study disordered systems and find that while fundamental modes are already trapped in a weakly disorder array, dipoles still diffract across the lattice.
Impedance of rigid bodies in one-dimensional elastic collisions
Santos, Janilo; de Oliveira, Bruna P. W.; Nelson,Osman Rosso
2012-01-01
In this work we study the problem of one-dimensional elastic collisions of billiard balls, considered as rigid bodies, in a framework very different from the classical one presented in text books. Implementing the notion of impedance matching as a way to understand efficiency of energy transmission in elastic collisions, we find a solution which frames the problem in terms of this conception. We show that the mass of the ball can be seen as a measure of its impedance and verify that the probl...
One-dimensional hydrodynamic model generating a turbulent cascade
Matsumoto, Takeshi; Sakajo, Takashi
2016-05-01
As a minimal mathematical model generating cascade analogous to that of the Navier-Stokes turbulence in the inertial range, we propose a one-dimensional partial-differential-equation model that conserves the integral of the squared vorticity analog (enstrophy) in the inviscid case. With a large-scale random forcing and small viscosity, we find numerically that the model exhibits the enstrophy cascade, the broad energy spectrum with a sizable correction to the dimensional-analysis prediction, peculiar intermittency, and self-similarity in the dynamical system structure.
Quantum Simulations of One-Dimensional Nanostructures under Arbitrary Deformations
Koskinen, Pekka
2016-09-01
A powerful technique is introduced for simulating mechanical and electromechanical properties of one-dimensional nanostructures under arbitrary combinations of bending, twisting, and stretching. The technique is based on an unconventional control of periodic symmetry which eliminates artifacts due to deformation constraints and quantum finite-size effects and allows transparent electronic-structure analysis. Via density-functional tight-binding implementation, the technique demonstrates its utility by predicting nonlinear electromechanical properties in carbon nanotubes and abrupt behavior in the structural yielding of Au7 and Mo6 S6 nanowires. The technique drives simulations markedly closer to the realistic modeling of these slender nanostructures under experimental conditions.
Beam interactions in one-dimensional saturable waveguide arrays
Stepic, M; Rueter, C E; Shandarov, V; Kip, D; Stepic, Milutin; Smirnov, Eugene; Rueter, Christian E.; Shandarov, Vladimir; Kip, Detlef
2006-01-01
The interaction between two parallel beams in one-dimensional discrete saturable systems has been investigated using lithium niobate nonlinear waveguide arrays. When the beams are separated by one channel and in-phase it is possible to observe soliton fusion at low power levels. This new result is confirmed numerically. By increasing the power, soliton-like propagation of weakly-coupled beams occurs. When the beams are out-of-phase the most interesting result is the existence of oscillations which resemble the recently discovered Tamm oscillations.
Waves and instability in a one-dimensional microfluidic array
Liu, Bin; Feng, Yan
2012-01-01
Motion in a one-dimensional (1D) microfluidic array is simulated. Water droplets, dragged by flowing oil, are arranged in a single row, and due to their hydrodynamic interactions spacing between these droplets oscillates with a wave-like motion that is longitudinal or transverse. The simulation yields wave spectra that agree well with experiment. The wave-like motion has an instability which is confirmed to arise from nonlinearities in the interaction potential. The instability's growth is spatially localized. By selecting an appropriate correlation function, the interaction between the longitudinal and transverse waves is described.
Fragmented one dimensional man / El hombre unidimensional fragmentado
Directory of Open Access Journals (Sweden)
Juan Antonio Rodríguez del Pino
2013-10-01
Full Text Available Paraphrase the title of the famous essay by Herbert Marcuse, since the image has traditionally been generated of man, masculinity, has been one-dimensional. I mean, the man was characterized by traits and behaviors established and entrenched since ancient time, considering all other distinguishing signs as mere deviations from the normative improper. But observe that this undeniable reality, as analyzed various researchers through what has come to be called Men's studies, has proven to be a fallacy difficult to maintain throughout history and today turns into fallacious and ineffective against changes in our current existing corporate models.
Molecular nanostamp based on one-dimensional porphyrin polymers.
Kanaizuka, Katsuhiko; Izumi, Atsushi; Ishizaki, Manabu; Kon, Hiroki; Togashi, Takanari; Miyake, Ryosuke; Ishida, Takao; Tamura, Ryo; Haga, Masa-aki; Moritani, Youji; Sakamoto, Masatomi; Kurihara, Masato
2013-08-14
Surface design with unique functional molecules by a convenient one-pot treatment is an attractive project for the creation of smart molecular devices. We have employed a silane coupling reaction of porphyrin derivatives that form one-dimensional polymer wires on substrates. Our simple one-pot treatment of a substrate with porphyrin has successfully achieved the construction of nanoscale bamboo shoot structures. The nanoscale bamboo shoots on the substrates were characterized by atomic force microscopy (AFM), UV-vis spectra, and X-ray diffraction (XRD) measurements. The uneven and rigid nanoscale structure has been used as a stamp for constructing bamboo shoot structures of fullerene.
Dynamical Structure Factors of quasi-one-dimensional antiferromagnets
Hagemans, Rob; Caux, Jean-Sébastien; Maillet, Jean Michel
2007-03-01
For a long time it has been impossible to accurately calculate the dynamical structure factors (spin-spin correlators as a function of momentum and energy) of quasi-one-dimensional antiferromagnets. For integrable Heisenberg chains, the recently developed ABACUS method (a first-principles computational approach based on the Bethe Ansatz) now yields highly accurate (over 99% of the sum rule) results for the DSF for finite chains, allowing for a very precise description of neutron-scattering data over the full momentum and energy range. We show remarkable agreement between results obtained with ABACUS and experiment.
ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES
Directory of Open Access Journals (Sweden)
Nikola Stefanović
2007-06-01
Full Text Available In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic leadership style, leadership theory researchers use two dimensional matrices. The two-dimensional matrices define leadership styles on the basis of different parameters. By using these parameters, one can identify two-dimensional styles.
Strongly anisotropic wetting on one-dimensional nanopatterned surfaces.
Xia, Deying; Brueck, S R J
2008-09-01
This communication reports strongly anisotropic wetting behavior on one-dimensional nanopatterned surfaces. Contact angles, degree of anisotropy, and droplet distortion are measured on micro- and nanopatterned surfaces fabricated with interference lithography. Both the degree of anisotropy and the droplet distortion are extremely high as compared with previous reports because of the well-defined nanostructural morphology. The surface is manipulated to tune with the wetting from hydrophobic to hydrophilic while retaining the structural wetting anisotropy with a simple silica nanoparticle overcoat. The wetting mechanisms are discussed. Potential applications in microfluidic devices and evaporation-induced pattern formation are demonstrated.
Spiral Magnetic Order in the One-Dimensional Kondo Lattice
Institute of Scientific and Technical Information of China (English)
LIU Zhen-Rong; LI Zheng-Zhong; SHEN Rui
2001-01-01
The effects of c-f (conduction-f electrons) hybridization on the spiral spin magnetism in the one dimensional Kondo lattice are studied. By using the mean-field approximation, a close set of equations of the Green's functions with arbitrary wave vector Q for the spiral ordering of spins is deduced. The magnetic phase boundary between the spiral magnetism and ferromagnetism has been calculated approximately. From our qualitative results, one can find that the ferromagnetic region is enlarged due to the c f hybridization. Moreover, some new results reflecting the Kondo effect, such as the modified dispersion relation and the weakening of the localized magnetic moments are also obtained.
Obstacle Effects on One-Dimensional Translocation of ATPase
Institute of Scientific and Technical Information of China (English)
WANG Xian-Ju; AI Bao-Quan; LIU Liang-Gang
2002-01-01
We apply a general random walk model to the study of the ATPase's one-dimensional translocation along obstacle biological environment, and show the effects of random obstacles on the ATPase translocation along single stranded DNA. We find that the obstacle environment can reduce the lifetime of ATPase lattice-bound state which results in the inhibition of ATPase activity. We also carry out the ranges of rate constant of ATPase unidirectonal translocation and bidirectional translocation. Our results are consistent with the experiments and relevant theoretical consideration, and can be used to explain some physiological phenomena.
Longitudinal waves in one dimensional non-uniform waveguides
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
Wave approach is used to analyze the longitudinal wave motion in one dimensional non-uniform waveguides.With assumptions of constant wave velocity and no wave conversion,there exist four types of non-uniform rods and corresponding traveling wave solutions are investigated.The obtained results indicate that the kinetic energy is preserved as a constant and the wave amplitude is inversely proportional to square root of the cross-sectional area of the rod.Under certain condition,there exists a cut-off frequ...
Bloch oscillations in a one-dimensional spinor gas.
Gangardt, D M; Kamenev, A
2009-02-20
A force applied to a spin-flipped particle in a one-dimensional spinor gas may lead to Bloch oscillations of the particle's position and velocity. The existence of Bloch oscillations crucially depends on the viscous friction force exerted by the rest of the gas on the spin excitation. We evaluate the friction in terms of the quantum fluid parameters. In particular, we show that the friction is absent for integrable cases, such as an SU(2) symmetric gas of bosons or fermions. For small deviations from the exact integrability the friction is very weak, opening the possibility to observe Bloch oscillations.
Fourier's law for quasi-one-dimensional chaotic quantum systems
Seligman, Thomas H.; Weidenmüller, Hans A.
2011-05-01
We derive Fourier's law for a completely coherent quasi-one-dimensional chaotic quantum system coupled locally to two heat baths at different temperatures. We solve the master equation to first order in the temperature difference. We show that the heat conductance can be expressed as a thermodynamic equilibrium coefficient taken at some intermediate temperature. We use that expression to show that for temperatures large compared to the mean level spacing of the system, the heat conductance is inversely proportional to the level density and, thus, inversely proportional to the length of the system.
Multiple nonequilibrium steady states for one-dimensional heat flow.
Zhang, F; Isbister, D J; Evans, D J
2001-08-01
A nonequilibrium molecular dynamics model of heat flow in one-dimensional lattices is shown to have multiple steady states for any fixed heat field strength f(e) ranging from zero to a certain positive value. We demonstrate that, depending on the initial conditions, there are at least two possibilities for the system's evolution: (i) formation of a stable traveling wave (soliton), and (ii) chaotic motion throughout the entire simulation. The percentage of the soliton-generating trajectories is zero for small field strength f(e), but increases sharply to unity over a critical region of the parameter f(e).
Nonlocal separable potential in the one-dimensional Dirac equation
Energy Technology Data Exchange (ETDEWEB)
Calkin, M.G.; Kiang, D.; Nogami, Y.
1988-08-01
The one-dimensional Dirac equation is solved for a separable potential of the form of Lorentz scalar plus vector, (..beta..g+h)v(x)v(x'). Exact analytic solutions are obtained for bound and scattering states for arbitrary v(x). For a particular combination of the values of g and h, degeneracy of the bound state occurs, and total reflection also takes place for a certain incident energy. The limiting case, in which v(x) becomes a delta function, is discussed in detail.
One-Dimensional Metals Conjugated Polymers, Organic Crystals, Carbon Nanotubes
Roth, Siegmar
2004-01-01
Low-dimensional solids are of fundamental interest in materials science due to their anisotropic properties. Written not only for experts in the field, this book explains the important concepts behind their physics and surveys the most interesting one-dimensional systems and discusses their present and emerging applications in molecular scale electronics. The second edition of this successful book has been completely revised to include the remarkable achievements of the last ten years of research and applications. Chemists, polymer and materials scientists as well as students will find this bo
Andrews, David L
2015-01-01
Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas
Andrews, David L
2015-01-01
This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol
Andrews, David L
2015-01-01
Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov
Andrews, David L
2015-01-01
Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry
Ray, Samit K; Katiyar, Ajit K; Raychaudhuri, Arup K
2017-03-03
Remarkable progress has been made in the field of one-dimensional semiconductor nanostructures for electronic and photonic devices. Group-IV semiconductors and their heterostructures have dominated the years of success in microelectronic industry. However their use in photonic devices is limited since they exhibit poor optical activity due to indirect band gap nature of Si and Ge. Reducing their dimensions below a characteristic length scale of various fundamental parameters like exciton Bohr radius, phonon mean free path, critical size of magnetic domains, exciton diffusion length etc result in the significant modification of bulk properties. In particular, light emission from Si/Ge nanowires due to quantum confinement, strain induced band structure modification and impurity doping may lead to the integration of photonic components with mature silicon CMOS technology in near future. Several promising applications based on Si and Ge nanowires have already been well established and studied, while others are now at the early demonstration stage. The control over various forms of energy and carrier transport through the unconstrained dimension makes Si and Ge nanowires a promising platform to manufacture advanced solid-state devices. This review presents the progress of the research with emphasis on their potential application of Si/Ge nanowires and their heterostructures for electronic, photonic, sensing and energy devices.
One-dimensional Si/Ge nanowires and their heterostructures for multifunctional applications—a review
Ray, Samit K.; Katiyar, Ajit K.; Raychaudhuri, Arup K.
2017-03-01
Remarkable progress has been made in the field of one-dimensional semiconductor nanostructures for electronic and photonic devices. Group-IV semiconductors and their heterostructures have dominated the years of success in microelectronic industry. However their use in photonic devices is limited since they exhibit poor optical activity due to indirect band gap nature of Si and Ge. Reducing their dimensions below a characteristic length scale of various fundamental parameters like exciton Bohr radius, phonon mean free path, critical size of magnetic domains, exciton diffusion length etc result in the significant modification of bulk properties. In particular, light emission from Si/Ge nanowires due to quantum confinement, strain induced band structure modification and impurity doping may lead to the integration of photonic components with mature silicon CMOS technology in near future. Several promising applications based on Si and Ge nanowires have already been well established and studied, while others are now at the early demonstration stage. The control over various forms of energy and carrier transport through the unconstrained dimension makes Si and Ge nanowires a promising platform to manufacture advanced solid-state devices. This review presents the progress of the research with emphasis on their potential application of Si/Ge nanowires and their heterostructures for electronic, photonic, sensing and energy devices.
Quasi-Dirac points in one-dimensional graphene superlattices
Energy Technology Data Exchange (ETDEWEB)
Chen, C.H.; Tseng, P.; Hsueh, W.J., E-mail: hsuehwj@ntu.edu.tw
2016-08-26
Quasi-Dirac points (QDPs) with energy different from the traditional Dirac points (TDPs) have been found for the first time in one-dimensional graphene superlattices. The angular-averaged conductance reaches a minimum value at the QDPs, at which the Fano factor approaches 1/3. Surprisingly, the minimum conductance at these QDPs may be lower than that at the TDPs under certain conditions. This is remarkable as the minimum conductance attainable in graphene superlattices was believed to appear at TDPs. - Highlights: • Quasi-Dirac points (QDPs) are found for the first time in one-dimensional graphene superlattices. • The QDP is different from the traditional Dirac points (TDPs) in graphene superlattices. • The angular-averaged conductance reaches a minimum value at the QDPs, at which the Fano factor approaches 1/3. • The minimum conductance at these QDPs may be lower than that at the TDPs under certain conditions. • The minimum conductance attainable in graphene superlattices was believed to appear at TDPs.
One-Dimensional Forward–Forward Mean-Field Games
Gomes, Diogo A.
2016-11-01
While the general theory for the terminal-initial value problem for mean-field games (MFGs) has achieved a substantial progress, the corresponding forward–forward problem is still poorly understood—even in the one-dimensional setting. Here, we consider one-dimensional forward–forward MFGs, study the existence of solutions and their long-time convergence. First, we discuss the relation between these models and systems of conservation laws. In particular, we identify new conserved quantities and study some qualitative properties of these systems. Next, we introduce a class of wave-like equations that are equivalent to forward–forward MFGs, and we derive a novel formulation as a system of conservation laws. For first-order logarithmic forward–forward MFG, we establish the existence of a global solution. Then, we consider a class of explicit solutions and show the existence of shocks. Finally, we examine parabolic forward–forward MFGs and establish the long-time convergence of the solutions.
Neutron scattering studies of three one-dimensional antiferromagnets
Kenzelmann, M
2001-01-01
observed in the disordered phase of spin-1/2 chains. The magnetic order of the one-dimensional spin-1/2 XY antiferromagnet Cs sub 2 CoCl sub 4 was investigated using neutron diffraction. The magnetic structure has an ordering wave-vector (0, 0.5, 0.5) for T < 217 mK and the magnetic structure is a non-linear structure with the magnetic moments at a small angle to the b axis. Above a field of H = 2.1 T the magnetic order collapses in an apparent first order phase transition, suggesting a transition to a spin-liquid phase. Low-dimensional magnets with low-spin quantum numbers are ideal model systems for investigating strongly interacting macroscopic quantum ground states and their non-linear spin excitations. This thesis describes neutron scattering experiments of three one-dimensional low-spin antiferromagnets where strong quantum fluctuations lead to highly-correlated ground states and unconventional cooperative spin excitations. The excitation spectrum of the antiferromagnetic spin-1 Heisenberg chain CsNi...
One-Dimensional Forward–Forward Mean-Field Games
Energy Technology Data Exchange (ETDEWEB)
Gomes, Diogo A., E-mail: diogo.gomes@kaust.edu.sa; Nurbekyan, Levon; Sedjro, Marc [King Abdullah University of Science and Technology (KAUST), CEMSE Division (Saudi Arabia)
2016-12-15
While the general theory for the terminal-initial value problem for mean-field games (MFGs) has achieved a substantial progress, the corresponding forward–forward problem is still poorly understood—even in the one-dimensional setting. Here, we consider one-dimensional forward–forward MFGs, study the existence of solutions and their long-time convergence. First, we discuss the relation between these models and systems of conservation laws. In particular, we identify new conserved quantities and study some qualitative properties of these systems. Next, we introduce a class of wave-like equations that are equivalent to forward–forward MFGs, and we derive a novel formulation as a system of conservation laws. For first-order logarithmic forward–forward MFG, we establish the existence of a global solution. Then, we consider a class of explicit solutions and show the existence of shocks. Finally, we examine parabolic forward–forward MFGs and establish the long-time convergence of the solutions.
Bjorken flow in one-dimensional relativistic magnetohydrodynamics with magnetization
Pu, Shi; Rezzolla, Luciano; Rischke, Dirk H
2016-01-01
We study the one-dimensional, longitudinally boost-invariant motion of an ideal fluid with infinite conductivity in the presence of a transverse magnetic field, i.e., in the ideal transverse magnetohydrodynamical limit. In an extension of our previous work [1], we consider the fluid to have a non-zero magnetization. First, we assume a constant magnetic susceptibility $\\chi_{m}$ and consider an ultrarelativistic ideal gas equation of state. For a paramagnetic fluid (i.e., with $\\chi_{m}>0$), the decay of the energy density slows down since the fluid gains energy from the magnetic field. For a diamagnetic fluid (i.e., with $\\chi_{m}<0$), the energy density decays faster because it feeds energy into the magnetic field. Furthermore, when the magnetic field is taken to be external and to decay in proper time $\\tau$ with a power law $\\sim\\tau^{-a}$, two distinct solutions can be found depending on the values of $a$ and $\\chi_m$. Finally, we also solve the ideal magnetohydrodynamical equations for one-dimensional...
Bjorken flow in one-dimensional relativistic magnetohydrodynamics with magnetization
Pu, Shi; Roy, Victor; Rezzolla, Luciano; Rischke, Dirk H.
2016-04-01
We study the one-dimensional, longitudinally boost-invariant motion of an ideal fluid with infinite conductivity in the presence of a transverse magnetic field, i.e., in the ideal transverse magnetohydrodynamical limit. In an extension of our previous work Roy et al., [Phys. Lett. B 750, 45 (2015)], we consider the fluid to have a nonzero magnetization. First, we assume a constant magnetic susceptibility χm and consider an ultrarelativistic ideal gas equation of state. For a paramagnetic fluid (i.e., with χm>0 ), the decay of the energy density slows down since the fluid gains energy from the magnetic field. For a diamagnetic fluid (i.e., with χmlaw ˜τ-a, two distinct solutions can be found depending on the values of a and χm. Finally, we also solve the ideal magnetohydrodynamical equations for one-dimensional Bjorken flow with a temperature-dependent magnetic susceptibility and a realistic equation of state given by lattice-QCD data. We find that the temperature and energy density decay more slowly because of the nonvanishing magnetization. For values of the magnetic field typical for heavy-ion collisions, this effect is, however, rather small. It is only for magnetic fields about an order of magnitude larger than expected for heavy-ion collisions that the system is substantially reheated and the lifetime of the quark phase might be extended.
Hydrogen peroxide stabilization in one-dimensional flow columns
Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.
2011-09-01
Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.
Institute of Scientific and Technical Information of China (English)
范希智
2014-01-01
In order to investigate the function of one dimension photonic crystals(ODPCs) in frustrated total re-flection, multi-periodic ODPCs which was embodied in glass were designed. The visible transmitted spectra(VTS) of 5-periodic ODPCs using magnesium fluoride(MgF2) and zinc sulfide(ZnS) to make basic period were numerically evaluated and that the photonic tunneling effect(PTE) for visible light is presence in such ODPCs were clearly stated. By PTE, ODPCs with MgF2/ZnS became interference filters for TE visible light wave, although they are transmitting for TM visible light wave. And such ODPCs are still provided with photonic forbidden band for TE visible light wave, in spite of the decrease of thickness of MgF2 layer in basic period. The VTS of ODPCs with basic period con-taining centrosymmetric layers were also numerically evaluated and that the transmission peaks appeared in photonic forbidden band for ODPCs with S1and S3 structure and that the function of ODPCs with S2 structure is fixed were in-dicated.%为了考察一维光子晶体(ODPCs)受抑全反射的特殊作用，本文设计出置于玻璃中的多周期的一维光子晶体。对于用氟化镁(MgF2)和硫化锌(ZnS)为基本材料制作的5周期的ODPCs，利用传输矩阵法对其可见光波透射率谱进行数值计算。结果发现，这种ODPCs对于可见光存在光子隧穿效应。这种效应使ODPCs对TE可见光波来说是干涉截止滤光片，而对于TM可见光波是透射的。减少基本周期内MgF2层的厚度，发现ODPCs对TE可见光波来说依然有光子禁带效应。对ODPCs的一个基本周期层改变为中心对称层，利用相同的方法进行可见光波透射率谱的数值计算发现，S1和S3结构的ODPCs的禁带内出现多个透射峰；而S2结构的ODPCs其作用不变。
Crystallographic shear mechanisms in Rh one-dimensional oxides
Hernando, María; Boulahya, Khalid; Parras, Marina; González-Calbet, José M.
2005-02-01
Electron diffraction and high resolution electron microscopy have been used to characterize two new one-dimensional superstructures in the A sbnd Rh sbnd O system (A = Ca, Sr) related to the 2H-ABO 3-type. They are formed by the intergrowth of n A 3A'BO 6 blocks, showing the Sr 4RhO 6-type, with A 12A' 2B 8O 30 blocks, constituted by two A 3O 9 and two A 3A'O 6 layers alternating in the stacking sequence 1:1, leading to the A 27A' 7B 13O 60 ( n=5) and A 30A' 8B 14O 66 ( n=6) compositions. A crystallographic shear mechanism is proposed to describe the structural relationship between Sr 4RhO 6 (A 3A'BO 6-type) and the new superstructures.
One-dimensional modeling of piping flow erosion
Lachouette, Damien; Golay, Frédéric; Bonelli, Stéphane
2008-09-01
A process called "piping", which often occurs in water-retaining structures (earth-dams, dykes, levees), involving the formation and progression of a continuous tunnel between the upstream and downstream sides, is one of the main cause of structure failure. Starting with the diphasic flow volume equations and the jump equations including the erosion processes, a simplified one-dimensional model for two-phase piping flow erosion was developed. The numerical simulation based on constant input and output pressures showed that the particle concentration can be a significant factor at the very beginning of the process, resulting in the enlargement of the hole at the exit. However, it was concluded that this influence is a secondary factor: the dilute flow assumption, which considerably simplifies the description, is relevant here. To cite this article: D. Lachouette et al., C. R. Mecanique 336 (2008).
Impedance of rigid bodies in one-dimensional elastic collisions
Santos, Janilo; Nelson, Osman Rosso
2012-01-01
In this work we study the problem of one-dimensional elastic collisions of billiard balls, considered as rigid bodies, in a framework very different from the classical one presented in text books. Implementing the notion of impedance matching as a way to understand eficiency of energy transmission in elastic collisions, we find a solution which frames the problem in terms of this conception. We show that the mass of the ball can be seen as a measure of its impedance and verify that the problem of maximum energy transfer in elastic collisions can be thought of as a problem of impedance matching between different media. This approach extends the concept of impedance, usually associated with oscillatory systems, to system of rigid bodies.
One-dimensional long-range percolation: A numerical study
Gori, G.; Michelangeli, M.; Defenu, N.; Trombettoni, A.
2017-07-01
In this paper we study bond percolation on a one-dimensional chain with power-law bond probability C /rd +σ , where r is the distance length between distinct sites and d =1 . We introduce and test an order-N Monte Carlo algorithm and we determine as a function of σ the critical value Cc at which percolation occurs. The critical exponents in the range 0 introduction of a suitably defined effective dimension deff relating the long-range model with a short-range one in dimension deff. We finally present a formulation of our algorithm for bond percolation on general graphs, with order N efficiency on a large class of graphs including short-range percolation and translationally invariant long-range models in any spatial dimension d with σ >0 .
Configurational and energy landscape in one-dimensional Coulomb systems.
Varela, Lucas; Téllez, Gabriel; Trizac, Emmanuel
2017-02-01
We study a one-dimensional Coulomb system, where two charged colloids are neutralized by a collection of point counterions, with global neutrality. With temperature being given, two situations are addressed: Either the colloids are kept at fixed positions (canonical ensemble) or the force acting on the colloids is fixed (isobaric-isothermal ensemble). The corresponding partition functions are worked out exactly, in view of determining which arrangement of counterions is optimal. How many counterions should be in the confined segment between the colloids? For the remaining ions outside, is there a left-right symmetry breakdown? We evidence a cascade of transitions as system size is varied in the canonical treatment or as pressure is increased in the isobaric formulation.
The statistical distributions of one-dimensional “turbulence”
Peyrard, Michel
2004-06-01
We study a one-dimensional discrete analog of the von Kármán flow widely investigated in turbulence, made of a lattice of anharmonic oscillators excited by both ends in the presence of a dissipative term proportional to the second-order finite difference of the velocities, similar to the viscous term in a fluid. The dynamics of the model shows striking similarities with an actual turbulent flow, both at local and global scales. Calculations of the probability distribution function of velocity increments, extensively studied in turbulence, with a very large number of points in order to determine accurately the statistics of rare events, allow us to provide a meaningful comparison of different theoretical expressions of the PDFs.
Scale dependent partitioning of one-dimensional aperiodic set diffraction
Elkharrat, A.
2004-06-01
We give a multiresolution partition of pure point parts of diffraction patterns of one-dimensional aperiodic sets. When an aperiodic set is related to the Golden Ratio, denoted by tau, it is well known that the pure point part of its diffractive measure is supported by the extension ring of tau, denoted by mathbb{Z}[tau]. The partition we give is based on the formalism of the so called tau-integers, denoted by mathbb{Z}_tau. The set of tau-integers is a selfsimilar set obeying mathbb{Z}_tau/tau^{j-1}subsetmathbb{Z}_tau/tau^j subset mathbb{Z}_tau/tau^{j + 1} subsetmathbb{Z}[tau], jinmathbb{Z}. The pure point spectrum is then partitioned with respect to this “Russian doll” like sequence of subsets mathbb{Z}_tau/tau^j. Thus we deduce the partition of the pure point part of the diffractive measure of aperiodic sets.
Explicit Solutions for One-Dimensional Mean-Field Games
Prazeres, Mariana
2017-04-05
In this thesis, we consider stationary one-dimensional mean-field games (MFGs) with or without congestion. Our aim is to understand the qualitative features of these games through the analysis of explicit solutions. We are particularly interested in MFGs with a nonmonotonic behavior, which corresponds to situations where agents tend to aggregate. First, we derive the MFG equations from control theory. Then, we compute explicit solutions using the current formulation and examine their behavior. Finally, we represent the solutions and analyze the results. This thesis main contributions are the following: First, we develop the current method to solve MFG explicitly. Second, we analyze in detail non-monotonic MFGs and discover new phenomena: non-uniqueness, discontinuous solutions, empty regions and unhappiness traps. Finally, we address several regularization procedures and examine the stability of MFGs.
Numerical method of characteristics for one-dimensional blood flow
Acosta, Sebastian; Riviere, Beatrice; Penny, Daniel J; Rusin, Craig G
2014-01-01
Mathematical modeling at the level of the full cardiovascular system requires the numerical approximation of solutions to a one-dimensional nonlinear hyperbolic system describing flow in a single vessel. This model is often simulated by computationally intensive methods like finite elements and discontinuous Galerkin, while some recent applications require more efficient approaches (e.g. for real-time clinical decision support, phenomena occurring over multiple cardiac cycles, iterative solutions to optimization/inverse problems, and uncertainty quantification). Further, the high speed of pressure waves in blood vessels greatly restricts the time-step needed for stability in explicit schemes. We address both cost and stability by presenting an efficient and unconditionally stable method for approximating solutions to diagonal nonlinear hyperbolic systems. Theoretical analysis of the algorithm is given along with a comparison of our method to a discontinuous Galerkin implementation. Lastly, we demonstrate the ...
Study on pile drivability with one dimensional wave propagation theory
Institute of Scientific and Technical Information of China (English)
陈仁朋; 王仕方; 陈云敏
2003-01-01
Pile drivability is a key problem during the stage of design and construction installation of pile foundations. The solution to the one dimensional wave equation was used to determine the impact force at the top of a concrete pile for a given ram mass, cushion stiffness, and pile impedance. The kinematic equation of pile toe was established and solved based on wave equation theory. The movements of the pile top and pile toe were presented, which clearly showed the dynamic displacement, including rebound and penetration of pile top and toe. A parametric study was made with a full range of practical values of ram weight, cushion stiffness, dropheight, and pile impedance. Suggestions for optimizing the parameters were also presented. Comparisons between the results obtained by the present solution and in-situ measurements indicated the reliability and validity of the method.
Testing of a one dimensional model for Field II calibration
DEFF Research Database (Denmark)
Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten
2008-01-01
to the calibrated Field II program for 1, 4, and 10 cycle excitations. Two parameter sets were applied for modeling, one real valued Pz27 parameter set, manufacturer supplied, and one complex valued parameter set found in literature, Alguer´o et al. [11]. The latter implicitly accounts for attenuation. Results show......Field II is a program for simulating ultrasound transducer fields. It is capable of calculating the emitted and pulse-echoed fields for both pulsed and continuous wave transducers. To make it fully calibrated a model of the transducer’s electro-mechanical impulse response must be included. We...... examine an adapted one dimensional transducer model originally proposed by Willatzen [9] to calibrate Field II. This model is modified to calculate the required impulse responses needed by Field II for a calibrated field pressure and external circuit current calculation. The testing has been performed...
Automated quantification of one-dimensional nanostructure alignment on surfaces
Dong, Jianjin; Abukhdeir, Nasser Mohieddin
2016-01-01
A method for automated quantification of the alignment of one-dimensional nanostructures from microscopy imaging is presented. Nanostructure alignment metrics are formulated and shown to able to rigorously quantify the orientational order of nanostructures within a two-dimensional domain (surface). A complementary image processing method is also presented which enables robust processing of microscopy images where overlapping nanostructures might be present. Scanning electron microscopy (SEM) images of nanowire-covered surfaces are analyzed using the presented methods and it is shown that past single parameter alignment metrics are insufficient for highly aligned domains. Through the use of multiple parameter alignment metrics, automated quantitative analysis of SEM images is shown to be possible and the alignment characteristics of different samples are able to be rigorously compared using a similarity metric. The results of this work provide researchers in nanoscience and nanotechnology with a rigorous metho...
A Reduced Order, One Dimensional Model of Joint Response
Energy Technology Data Exchange (ETDEWEB)
DOHNER,JEFFREY L.
2000-11-06
As a joint is loaded, the tangent stiffness of the joint reduces due to slip at interfaces. This stiffness reduction continues until the direction of the applied load is reversed or the total interface slips. Total interface slippage in joints is called macro-slip. For joints not undergoing macro-slip, when load reversal occurs the tangent stiffness immediately rebounds to its maximum value. This occurs due to stiction effects at the interface. Thus, for periodic loads, a softening and rebound hardening cycle is produced which defines a hysteretic, energy absorbing trajectory. For many jointed sub-structures, this hysteretic trajectory can be approximated using simple polynomial representations. This allows for complex joint substructures to be represented using simple non-linear models. In this paper a simple one dimensional model is discussed.
Singularity formation for one dimensional full Euler equations
Pan, Ronghua; Zhu, Yi
2016-12-01
We investigate the basic open question on the global existence v.s. finite time blow-up phenomena of classical solutions for the one-dimensional compressible Euler equations of adiabatic flow. For isentropic flows, it is well-known that the solutions develop singularity if and only if initial data contain any compression (the Riemann variables have negative spatial derivative). The situation for non-isentropic flow is not quite clear so far, due to the presence of non-constant entropy. In [4], it is shown that initial weak compressions do not necessarily develop singularity in finite time, unless the compression is strong enough for general data. In this paper, we identify a class of solutions of the full (non-isentropic) Euler equations, developing singularity in finite time even though their initial data do not contain any compression. This is in sharp contrast to the isentropic flow.
One-dimensional topological edge states of bismuth bilayers
Drozdov, Ilya K.; Alexandradinata, A.; Jeon, Sangjun; Nadj-Perge, Stevan; Ji, Huiwen; Cava, R. J.; Andrei Bernevig, B.; Yazdani, Ali
2014-09-01
The hallmark of a topologically insulating state of matter in two dimensions protected by time-reversal symmetry is the existence of chiral edge modes propagating along the perimeter of the sample. Among the first systems predicted to be a two-dimensional topological insulator are bilayers of bismuth. Here we report scanning tunnelling microscopy experiments on bulk Bi crystals that show that a subset of the predicted Bi-bilayers' edge states are decoupled from the states of the substrate and provide direct spectroscopic evidence of their one-dimensional nature. Moreover, by visualizing the quantum interference of edge-mode quasi-particles in confined geometries, we demonstrate their remarkable coherent propagation along the edge with scattering properties consistent with strong suppression of backscattering as predicted for the propagating topological edge states.
Spin accumulation on a one-dimensional mesoscopic Rashba ring
Energy Technology Data Exchange (ETDEWEB)
Zhang Zhiyong [Department of Physics, Nanjing University, Nanjing 210093 (China)
2006-04-26
The nonequilibrium spin accumulation on a one-dimensional (1D) mesoscopic Rashba ring is investigated with unpolarized current injected through ideal leads. Due to the Rashba spin-orbit (SO) coupling and back-scattering at the interfaces between the leads and the ring, a beating pattern is formed in the fast oscillation of spin accumulation. If every beating period is complete, a plateau is formed, where the variation of spin accumulation with the external voltage is slow, but if new incomplete periods emerge in the envelope function, a transitional region appears. This plateau structure and the beating pattern are related to the tunnelling through spin-dependent resonant states. Because of the Aharonov-Casher (AC) effect, the average spin accumulation oscillates quasi-periodically with the Rashba SO coupling and has a series of zeros. In some situations, the direction of the average spin accumulation can be reversed by the external voltage in this 1D Rashba ring.
Spin accumulation on a one-dimensional mesoscopic Rashba ring.
Zhang, Zhi-Yong
2006-04-26
The nonequilibrium spin accumulation on a one-dimensional (1D) mesoscopic Rashba ring is investigated with unpolarized current injected through ideal leads. Due to the Rashba spin-orbit (SO) coupling and back-scattering at the interfaces between the leads and the ring, a beating pattern is formed in the fast oscillation of spin accumulation. If every beating period is complete, a plateau is formed, where the variation of spin accumulation with the external voltage is slow, but if new incomplete periods emerge in the envelope function, a transitional region appears. This plateau structure and the beating pattern are related to the tunnelling through spin-dependent resonant states. Because of the Aharonov-Casher (AC) effect, the average spin accumulation oscillates quasi-periodically with the Rashba SO coupling and has a series of zeros. In some situations, the direction of the average spin accumulation can be reversed by the external voltage in this 1D Rashba ring.
One-dimensional hybrid nanostructures for heterogeneous photocatalysis and photoelectrocatalysis.
Xiao, Fang-Xing; Miao, Jianwei; Tao, Hua Bing; Hung, Sung-Fu; Wang, Hsin-Yi; Yang, Hong Bin; Chen, Jiazang; Chen, Rong; Liu, Bin
2015-05-13
Semiconductor-based photocatalysis and photoelectrocatalysis have received considerable attention as alternative approaches for solar energy harvesting and storage. The photocatalytic or photoelectrocatalytic performance of a semiconductor is closely related to the design of the semiconductor at the nanoscale. Among various nanostructures, one-dimensional (1D) nanostructured photocatalysts and photoelectrodes have attracted increasing interest owing to their unique optical, structural, and electronic advantages. In this article, a comprehensive review of the current research efforts towards the development of 1D semiconductor nanomaterials for heterogeneous photocatalysis and photoelectrocatalysis is provided and, in particular, a discussion of how to overcome the challenges for achieving full potential of 1D nanostructures is presented. It is anticipated that this review will afford enriched information on the rational exploration of the structural and electronic properties of 1D semiconductor nanostructures for achieving more efficient 1D nanostructure-based photocatalysts and photoelectrodes for high-efficiency solar energy conversion.
Polaron and bipolaron of uniaxially strained one dimensional zigzag ladder
Energy Technology Data Exchange (ETDEWEB)
Yavidov, B.Ya., E-mail: bakhrom.yavidov@gmail.com
2016-09-15
An influence of the uniaxial strains in one dimensional zigzag ladder (1DZL) on the properties of polarons and bipolarons is considered. It is shown that strain changes all the parameters of the system, in particular, spectrum, existing bands and the masses of charge carriers. Numerical results obtained by taking into an account the Poisson effect clearly indicate that the properties of the (bi)polaronic system can be tuned via strain. Mass of bipolaron can be manipulated by the strain too which in turn leads to the way of tuning Bose–Einstein condensation temperature T{sub BEC} of bipolarons. It is shown that T{sub BEC} of bipolarons in strained 1DZL reasonably correlates with the values of critical temperature of superconductivity of certain perovskites.
One-dimensional quasi-relativistic particle in the box
Kaleta, Kamil; Malecki, Jacek
2011-01-01
Two-term Weyl-type asymptotic law for the eigenvalues of one-dimensional quasi-relativistic Hamiltonian (-h^2 c^2 d^2/dx^2 + m^2 c^4)^(1/2) + V_well(x) (the Klein-Gordon square-root operator with electrostatic potential) with the infinite square well potential V_well(x) is given: the n-th eigenvalue is equal to (n pi/2 - pi/8) h c/a + O(1/n), where 2a is the width of the potential well. Simplicity of eigenvalues is proved. Some L^2 and L^infinity properties of eigenfunctions are also studied. Eigenvalues represent energies of a `massive particle in the box' quasi-relativistic model.
Novel superconducting phenomena in quasi-one-dimensional Bechgaard salts
Jerome, Denis; Yonezawa, Shingo
2016-03-01
It is the saturation of the transition temperature Tc in the range of 24 K for known materials in the late sixties that triggered the search for additional materials offering new coupling mechanisms leading in turn to higher Tc's. As a result of this stimulation, superconductivity in organic matter was discovered in tetramethyl-tetraselenafulvalene-hexafluorophosphate, (TMTSF)2PF6, in 1979, in the laboratory founded at Orsay by Professor Friedel and his colleagues in 1962. Although this conductor is a prototype example for low-dimensional physics, we mostly focus in this article on the superconducting phase of the ambient-pressure superconductor (TMTSF)2ClO4, which has been studied most intensively among the TMTSF salts. We shall present a series of experimental results supporting nodal d-wave symmetry for the superconducting gap in these prototypical quasi-one-dimensional conductors. xml:lang="fr"
One-Dimensional Time to Explosion (Thermal Sensitivity) of ANPZ
Energy Technology Data Exchange (ETDEWEB)
Hsu, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hust, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McClelland, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gresshoff, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2014-11-12
Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 C) and the violence from thermal explosion may cause a significant damage. Thus it is important to understand the response of energetic materials to thermal insults. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to explosion, threshold thermal explosion temperature, and determine kinetic parameters of energetic materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. The ODTX testing can also provide useful data for assessing the thermal explosion violence of energetic materials. This report summarizes the recent ODTX experimental data and modeling results for 2,6-diamino-3,5-dintropyrazine (ANPZ).
Capillary condensation in one-dimensional irregular confinement
Handford, Thomas P.; Pérez-Reche, Francisco J.; Taraskin, Sergei N.
2013-07-01
A lattice-gas model with heterogeneity is developed for the description of fluid condensation in finite sized one-dimensional pores of arbitrary shape. Mapping to the random-field Ising model allows an exact solution of the model to be obtained at zero-temperature, reproducing the experimentally observed dependence of the amount of fluid adsorbed in the pore on external pressure. It is demonstrated that the disorder controls the sorption for long pores and can result in H2-type hysteresis. Finite-temperature Metropolis dynamics simulations support analytical findings in the limit of low temperatures. The proposed framework is viewed as a fundamental building block of the theory of capillary condensation necessary for reliable structural analysis of complex porous media from adsorption-desorption data.
Compaction of quasi-one-dimensional elastoplastic materials
Shaebani, M. Reza; Najafi, Javad; Farnudi, Ali; Bonn, Daniel; Habibi, Mehdi
2017-06-01
Insight into crumpling or compaction of one-dimensional objects is important for understanding biopolymer packaging and designing innovative technological devices. By compacting various types of wires in rigid confinements and characterizing the morphology of the resulting crumpled structures, here, we report how friction, plasticity and torsion enhance disorder, leading to a transition from coiled to folded morphologies. In the latter case, where folding dominates the crumpling process, we find that reducing the relative wire thickness counter-intuitively causes the maximum packing density to decrease. The segment size distribution gradually becomes more asymmetric during compaction, reflecting an increase of spatial correlations. We introduce a self-avoiding random walk model and verify that the cumulative injected wire length follows a universal dependence on segment size, allowing for the prediction of the efficiency of compaction as a function of material properties, container size and injection force.
Reprint of : Absorbing/Emitting Phonons with one dimensional MOSFETs
Bosisio, Riccardo; Gorini, Cosimo; Fleury, Geneviève; Pichard, Jean-Louis
2016-08-01
We consider nanowires in the field effect transistor device configuration. Modeling each nanowire as a one dimensional lattice with random site potentials, we study the heat exchanges between the nanowire electrons and the substrate phonons, when electron transport is due to phonon-assisted hops between localized states. Shifting the nanowire conduction band with a metallic gate induces different behaviors. When the Fermi potential is located near the band center, a bias voltage gives rise to small local heat exchanges which fluctuate randomly along the nanowire. When it is located near one of the band edges, the bias voltage yields heat currents which flow mainly from the substrate towards the nanowire near one boundary of the nanowire, and in the opposite direction near the other boundary. This opens interesting perspectives for heat management at submicron scales: arrays of parallel gated nanowires could be used for a field control of phonon emission/absorption.
Charge diffusion in the one-dimensional Hubbard model
Steinigeweg, R.; Jin, F.; De Raedt, H.; Michielsen, K.; Gemmer, J.
2017-08-01
We study the real-time and real-space dynamics of charge in the one-dimensional Hubbard model in the limit of high temperatures. To this end, we prepare pure initial states with sharply peaked density profiles and calculate the time evolution of these nonequilibrium states, by using numerical forward-propagation approaches to chains as long as 20 sites. For a class of typical states, we find excellent agreement with linear-response theory and unveil the existence of remarkably clean charge diffusion in the regime of strong particle-particle interactions. We additionally demonstrate that, in the half-filling sector, this diffusive behavior does not depend on certain details of our initial conditions, i.e., it occurs for five different realizations with random and nonrandom internal degrees of freedom, single and double occupation of the central site, and displacement of spin-up and spin-down particles.
Analytical models of optical response in one-dimensional semiconductors
Energy Technology Data Exchange (ETDEWEB)
Pedersen, Thomas Garm, E-mail: tgp@nano.aau.dk
2015-09-04
The quantum mechanical description of the optical properties of crystalline materials typically requires extensive numerical computation. Including excitonic and non-perturbative field effects adds to the complexity. In one dimension, however, the analysis simplifies and optical spectra can be computed exactly. In this paper, we apply the Wannier exciton formalism to derive analytical expressions for the optical response in four cases of increasing complexity. Thus, we start from free carriers and, in turn, switch on electrostatic fields and electron–hole attraction and, finally, analyze the combined influence of these effects. In addition, the optical response of impurity-localized excitons is discussed. - Highlights: • Optical response of one-dimensional semiconductors including excitons. • Analytical model of excitonic Franz–Keldysh effect. • Computation of optical response of impurity-localized excitons.
A one-dimensional toy model of globular clusters
Fanelli, D; Ruffo, S; Fanelli, Duccio; Merafina, Marco; Ruffo, Stefano
2001-01-01
We introduce a one-dimensional toy model of globular clusters. The model is a version of the well-known gravitational sheets system, where we take additionally into account mass and energy loss by evaporation of stars at the boundaries. Numerical integration by the "exact" event-driven dynamics is performed, for initial uniform density and Gaussian random velocities. Two distinct quasi-stationary asymptotic regimes are attained, depending on the initial energy of the system. We guess the forms of the density and velocity profiles which fit numerical data extremely well and allow to perform an independent calculation of the self-consistent gravitational potential. Some power-laws for the asymptotic number of stars and for the collision times are suggested.
Magnons in one-dimensional k-component Fibonacci structures
Costa, C. H.; Vasconcelos, M. S.
2014-05-01
We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: Sn(k)=Sn-1(k)Sn-k(k) (n ≥k=0,1,2,…), where Sn(k) is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.
Magnons in one-dimensional k-component Fibonacci structures
Energy Technology Data Exchange (ETDEWEB)
Costa, C. H., E-mail: carloshocosta@hotmail.com [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Vasconcelos, M. S. [Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil)
2014-05-07
We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: S{sub n}{sup (k)}=S{sub n−1}{sup (k)}S{sub n−k}{sup (k)} (n≥k=0,1,2,…), where S{sub n}{sup (k)} is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.
Well-posedness of one-dimensional Korteweg models
Directory of Open Access Journals (Sweden)
Sylvie Benzoni-Gavage
2006-05-01
Full Text Available We investigate the initial-value problem for one-dimensional compressible fluids endowed with internal capillarity. We focus on the isothermal inviscid case with variable capillarity. The resulting equations for the density and the velocity, consisting of the mass conservation law and the momentum conservation with Korteweg stress, are a system of third order nonlinear dispersive partial differential equations. Additionally, this system is Hamiltonian and admits travelling solutions, representing propagating phase boundaries with internal structure. By change of unknown, it roughly reduces to a quasilinear Schrodinger equation. This new formulation enables us to prove local well-posedness for smooth perturbations of travelling profiles and almost-global existence for small enough perturbations. A blow-up criterion is also derived.
Magnetic properties of manganese based one-dimensional spin chains.
Asha, K S; Ranjith, K M; Yogi, Arvind; Nath, R; Mandal, Sukhendu
2015-12-14
We have correlated the structure-property relationship of three manganese-based inorganic-organic hybrid structures. Compound 1, [Mn2(OH-BDC)2(DMF)3] (where BDC = 1,4-benzene dicarboxylic acid and DMF = N,N'-dimethylformamide), contains Mn2O11 dimers as secondary building units (SBUs), which are connected by carboxylate anions forming Mn-O-C-O-Mn chains. Compound 2, [Mn2(BDC)2(DMF)2], contains Mn4O20 clusters as SBUs, which also form Mn-O-C-O-Mn chains. In compound 3, [Mn3(BDC)3(DEF)2] (where DEF = N,N'-diethylformamide), the distorted MnO6 octahedra are linked to form a one-dimensional chain with Mn-O-Mn connectivity. The magnetic properties were investigated by means of magnetization and heat capacity measurements. The temperature dependent magnetic susceptibility of all the three compounds could be nicely fitted using a one-dimensional S = 5/2 Heisenberg antiferromagnetic chain model and the value of intra-chain exchange coupling (J/k(B)) between Mn(2+) ions was estimated to be ∼1.1 K, ∼0.7 K, and ∼0.46 K for compounds 1, 2, and 3, respectively. Compound 1 does not undergo any magnetic long-range-order down to 2 K while compounds 2 and 3 undergo long-range magnetic order at T(N) ≈ 4.2 K and ≈4.3 K, respectively, which are of spin-glass type. From the values of J/k(B) and T(N) the inter-chain coupling (J(⊥)/k(B)) was calculated to be about 0.1J/k(B) for both compounds 2 and 3, respectively.
A One-Dimensional Synthetic-Aperture Microwave Radiometer
Doiron, Terence; Piepmeier, Jeffrey
2010-01-01
A proposed one-dimensional synthetic- aperture microwave radiometer could serve as an alternative to either the two-dimensional synthetic-aperture radiometer described in the immediately preceding article or to a prior one-dimensional one, denoted the Electrically Scanned Thinned Array Radiometer (ESTAR), mentioned in that article. The proposed radiometer would operate in a pushbroom imaging mode, utilizing (1) interferometric cross-track scanning to obtain cross-track resolution and (2) the focusing property of a reflector for along-track resolution. The most novel aspect of the proposed system would be the antenna (see figure), which would include a cylindrical reflector of offset parabolic cross section. The reflector could be made of a lightweight, flexible material amenable to stowage and deployment. Other than a stowage/deployment mechanism, the antenna would not include moving parts, and cross-track scanning would not entail mechanical rotation of the antenna. During operation, the focal line, parallel to the cylindrical axis, would be oriented in the cross-track direction, so that placement of receiving/radiating elements at the focal line would afford the desired along-track resolution. The elements would be microwave feed horns sparsely arrayed along the focal line. The feed horns would be oriented with their short and long cross-sectional dimensions parallel and perpendicular, respectively, to the cylindrical axis to obtain fan-shaped beams having their broad and narrow cross-sectional dimensions parallel and perpendicular, respectively, to the cylindrical axis. The interference among the beams would be controlled in the same manner as in the ESTAR to obtain along-cylindrical- axis (cross-track) resolution and cross-track scanning.
Novel Method of Detecting Movement of the Interference Fringes Using One-Dimensional PSD
Directory of Open Access Journals (Sweden)
Qi Wang
2015-06-01
Full Text Available In this paper, a method of using a one-dimensional position-sensitive detector (PSD by replacing charge-coupled device (CCD to measure the movement of the interference fringes is presented first, and its feasibility is demonstrated through an experimental setup based on the principle of centroid detection. Firstly, the centroid position of the interference fringes in a fiber Mach-Zehnder (M-Z interferometer is solved in theory, showing it has a higher resolution and sensitivity. According to the physical characteristics and principles of PSD, a simulation of the interference fringe’s phase difference in fiber M-Z interferometers and PSD output is carried out. Comparing the simulation results with the relationship between phase differences and centroid positions in fiber M-Z interferometers, the conclusion that the output of interference fringes by PSD is still the centroid position is obtained. Based on massive measurements, the best resolution of the system is achieved with 5.15, 625 μm. Finally, the detection system is evaluated through setup error analysis and an ultra-narrow-band filter structure. The filter structure is configured with a one-dimensional photonic crystal containing positive and negative refraction material, which can eliminate background light in the PSD detection experiment. This detection system has a simple structure, good stability, high precision and easily performs remote measurements, which makes it potentially useful in material small deformation tests, refractivity measurements of optical media and optical wave front detection.
Quantized impedance dealing with the damping behavior of the one-dimensional oscillator
Energy Technology Data Exchange (ETDEWEB)
Zhu, Jinghao; Zhang, Jing; Li, Yuan; Zhang, Yong; Fang, Zhengji; Zhao, Peide, E-mail: pdzhao@eyou.com, E-mail: pdzhao@hebut.edu.cn [School of Science, Hebei University of Technology, Beichen Campus, Tianjin 300401 (China); Li, Erping, E-mail: liep@zju.edu.cn [Institute of High Performance Computing, Fusionopolis, 1 Fusionopolis Way, No. 16-16 Connexis, Singapore 138632 (Singapore)
2015-11-15
A quantized impedance is proposed to theoretically establish the relationship between the atomic eigenfrequency and the intrinsic frequency of the one-dimensional oscillator in this paper. The classical oscillator is modified by the idea that the electron transition is treated as a charge-discharge process of a suggested capacitor with the capacitive energy equal to the energy level difference of the jumping electron. The quantized capacitance of the impedance interacting with the jumping electron can lead the resonant frequency of the oscillator to the same as the atomic eigenfrequency. The quantized resistance reflects that the damping coefficient of the oscillator is the mean collision frequency of the transition electron. In addition, the first and third order electric susceptibilities based on the oscillator are accordingly quantized. Our simulation of the hydrogen atom emission spectrum based on the proposed method agrees well with the experimental one. Our results exhibits that the one-dimensional oscillator with the quantized impedance may become useful in the estimations of the refractive index and one- or multi-photon absorption coefficients of some nonmagnetic media composed of hydrogen-like atoms.
Novel method of detecting movement of the interference fringes using one-dimensional PSD.
Wang, Qi; Xia, Ji; Liu, Xu; Zhao, Yong
2015-06-02
In this paper, a method of using a one-dimensional position-sensitive detector (PSD) by replacing charge-coupled device (CCD) to measure the movement of the interference fringes is presented first, and its feasibility is demonstrated through an experimental setup based on the principle of centroid detection. Firstly, the centroid position of the interference fringes in a fiber Mach-Zehnder (M-Z) interferometer is solved in theory, showing it has a higher resolution and sensitivity. According to the physical characteristics and principles of PSD, a simulation of the interference fringe's phase difference in fiber M-Z interferometers and PSD output is carried out. Comparing the simulation results with the relationship between phase differences and centroid positions in fiber M-Z interferometers, the conclusion that the output of interference fringes by PSD is still the centroid position is obtained. Based on massive measurements, the best resolution of the system is achieved with 5.15, 625 μm. Finally, the detection system is evaluated through setup error analysis and an ultra-narrow-band filter structure. The filter structure is configured with a one-dimensional photonic crystal containing positive and negative refraction material, which can eliminate background light in the PSD detection experiment. This detection system has a simple structure, good stability, high precision and easily performs remote measurements, which makes it potentially useful in material small deformation tests, refractivity measurements of optical media and optical wave front detection.
Pulsed second-harmonic generation in nonlinear, one-dimensional, periodic structures
Scalora, M.; Bloemer, M. J.; Manka, A. S.; Dowling, J. P.; Bowden, C. M.; Viswanathan, R.; Haus, J. W.
1997-10-01
We present a numerical study of second-harmonic (SH) generation in a one-dimensional, generic, photonic band-gap material that is doped with a nonlinear χ(2) medium. We show that a 20-period, 12-μm structure can generate short SH pulses (similar in duration to pump pulses) whose energy and power levels may be 2-3 orders of magnitude larger than the energy and power levels produced by an equivalent length of a phase-matched, bulk medium. This phenomenon comes about as a result of the combination of high electromagnetic mode density of states, low group velocity, and spatial phase locking of the fields near the photonic band edge. The structure is designed so that the pump pulse is tuned near the first-order photonic band edge, and the SH signal is generated near the band edge of the second-order gap. This maximizes the density of available field modes for both the pump and SH field. Our results show that the χ(2) response is effectively enhanced by several orders of magnitude. Therefore, mm- or cm-long, quasi-phase-matched devices could be replaced by these simple layered structures of only a few micrometers in length. This has important applications to high-energy lasers, Raman-type sources, and frequency up- and down-conversion schemes.
Creating cat states in one-dimensional quantum walks using delocalized initial states
Zhang, Wei-Wei; Goyal, Sandeep K.; Gao, Fei; Sanders, Barry C.; Simon, Christoph
2016-09-01
Cat states are coherent quantum superpositions of macroscopically distinct states and are useful for understanding the boundary between the classical and the quantum world. Due to their macroscopic nature, cat states are difficult to prepare in physical systems. We propose a method to create cat states in one-dimensional quantum walks using delocalized initial states of the walker. Since the quantum walks can be performed on any quantum system, our proposal enables a platform-independent realization of the cat states. We further show that the linear dispersion relation of the effective quantum walk Hamiltonian, which governs the dynamics of the delocalized states, is responsible for the formation of the cat states. We analyze the robustness of these states against environmental interactions and present methods to control and manipulate the cat states in the photonic implementation of quantum walks.
Strongly coupled slow-light polaritons in one-dimensional disordered localized states
Gao, Jie; Liang, Baolai; Schmitteckert, Peter; Lehoucq, Gaelle; Xavier, Stephane; Xu, Xinan; Busch, Kurt; Huffaker, Diana L; De Rossi, Alfredo; Wong, Chee Wei
2013-01-01
Cavity quantum electrodynamics advances the coherent control of a single quantum emitter with a quantized radiation field mode, typically piecewise engineered for the highest finesse and confinement in the cavity field. This enables the possibility of strong coupling for chip-scale quantum processing, but till now is limited to few research groups that can achieve the precision and deterministic requirements for these polariton states. Here we observe for the first time coherent polariton states of strong coupled single quantum dot excitons in inherently disordered one-dimensional localized modes in slow-light photonic crystals. Large vacuum Rabi splittings up to 311 {\\mu}eV are observed, one of the largest avoided crossings in the solid-state. Our tight-binding models with quantum impurities detail these strong localized polaritons, spanning different disorder strengths, complementary to model-extracted pure dephasing and incoherent pumping rates. Such disorder-induced slow-light polaritons provide a platfor...
Creating cat states in one-dimensional quantum walks using delocalized initial states
Zhang, Wei-Wei; Gao, Fei; Sanders, Barry C; Simon, Christoph
2016-01-01
Cat states are coherent quantum superpositions of macroscopically distinct states, and are useful for understanding the boundary between the classical and the quantum world. Due to their macroscopic nature, cat states are difficult to prepare in physical systems. We propose a method to realize the cat states in one-dimensional quantum walks using delocalized initial states of the walker. We show that the linear dispersion relation of the effective quantum walk Hamiltonian, which governs the dynamics of the delocalized states, is responsible for the formation of the cat states. We analyze the robustness of these states against the environmental interactions. We present methods to control and manipulate the cat states in the photonic implementation of quantum walks.
Large Bragg Reflection from One-Dimensional Chains of Trapped Atoms Near a Nanoscale Waveguide
Corzo, N V; Chandra, A; Goban, A; Sheremet, A S; Kupriyanov, D V; Laurat, J
2016-01-01
We report experimental observations of large Bragg reflection from arrays of cold atoms trapped near a one-dimensional nanoscale waveguide. By using an optical lattice in the evanescent field surrounding a nanofiber with a period close to commensurate with the resonant wavelength, we observe a reflectance up to 75% for the guided mode. Each atom behaves as a partially-reflecting mirror and an ordered chain of about 2000 atoms is sufficient to realize an efficient Bragg mirror. Measurements of the reflection spectra as a function of the lattice period and the probe polarization are reported. The latter shows the effect of the chiral character of nanoscale waveguides on this reflection. The ability to control photon transport in 1D waveguides coupled to spin systems would allow for novel quantum network capabilities and many-body effects emerging from long-range interactions.
Large Bragg Reflection from One-Dimensional Chains of Trapped Atoms Near a Nanoscale Waveguide
Corzo, Neil V.; Gouraud, Baptiste; Chandra, Aveek; Goban, Akihisa; Sheremet, Alexandra S.; Kupriyanov, Dmitriy V.; Laurat, Julien
2016-09-01
We report experimental observations of a large Bragg reflection from arrays of cold atoms trapped near a one-dimensional nanoscale waveguide. By using an optical lattice in the evanescent field surrounding a nanofiber with a period nearly commensurate with the resonant wavelength, we observe a reflectance of up to 75% for the guided mode. Each atom behaves as a partially reflecting mirror and an ordered chain of about 2000 atoms is sufficient to realize an efficient Bragg mirror. Measurements of the reflection spectra as a function of the lattice period and the probe polarization are reported. The latter shows the effect of the chiral character of nanoscale waveguides on this reflection. The ability to control photon transport in 1D waveguides coupled to spin systems would enable novel quantum network capabilities and the study of many-body effects emerging from long-range interactions.
Charge transport through one-dimensional Moiré crystals
Bonnet, Roméo; Lherbier, Aurélien; Barraud, Clément; Rocca, Maria Luisa Della; Lafarge, Philippe; Charlier, Jean-Christophe
2016-01-01
Moiré superlattices were generated in two-dimensional (2D) van der Waals heterostructures and have revealed intriguing electronic structures. The appearance of mini-Dirac cones within the conduction and valence bands of graphene is one of the most striking among the new quantum features. A Moiré superstructure emerges when at least two periodic sub-structures superimpose. 2D Moiré patterns have been particularly investigated in stacked hexagonal 2D atomic lattices like twisted graphene layers and graphene deposited on hexagonal boron-nitride. In this letter, we report both experimentally and theoretically evidence of superlattices physics in transport properties of one-dimensional (1D) Moiré crystals. Rolling-up few layers of graphene to form a multiwall carbon nanotube adds boundaries conditions that can be translated into interference fringes-like Moiré patterns along the circumference of the cylinder. Such a 1D Moiré crystal exhibits a complex 1D multiple bands structure with clear and robust interband quantum transitions due to the presence of mini-Dirac points and pseudo-gaps. Our devices consist in a very large diameter (>80 nm) multiwall carbon nanotubes of high quality, electrically connected by metallic electrodes acting as charge reservoirs. Conductance measurements reveal the presence of van Hove singularities assigned to 1D Moiré superlattice effect and illustrated by electronic structure calculations.
One-dimensional consolidation in unsaturated soils under cyclic loading
Lo, Wei-Cheng; Sposito, Garrison; Lee, Jhe-Wei; Chu, Hsiuhua
2016-05-01
The one-dimensional consolidation model of poroelasticity of Lo et al. (2014) for an unsaturated soil under constant loading is generalized to include an arbitrary time-dependent loading. A closed-form solution for the pore water and air pressures along with the total settlement is derived by employing a Fourier series representation in the spatial domain and a Laplace transformation in the time domain. This solution is illustrated for the important example of a fully-permeable soil cylinder with an undrained initial condition acted upon by a periodic stress. Our results indicate that, in terms of a dimensionless time scale, the transient solution decays to zero most slowly in a water-saturated soil, whereas for an unsaturated soil, the time for the transient solution to die out is inversely proportional to the initial water saturation. The generalization presented here shows that the diffusion time scale for pore water in an unsaturated soil is orders of magnitude greater than that in a water-saturated soil, mainly because of the much smaller hydraulic conductivity of the former.
Integral Transport Theory in One-dimensional Geometries
Energy Technology Data Exchange (ETDEWEB)
Carlvik, I.
1966-06-15
A method called DIT (Discrete Integral Transport) has been developed for the numerical solution of the transport equation in one-dimensional systems. The characteristic features of the method are Gaussian integration over the coordinate as described by Kobayashi and Nishihara, and a particular scheme for the calculation of matrix elements in annular and spherical geometry that has been used for collision probabilities in earlier Flurig programmes. The paper gives a general theory including such things as anisotropic scattering and multi-pole fluxes, and it gives a brief description of the Flurig scheme. Annular geometry is treated in some detail, and corresponding formulae are given for spherical and plane geometry. There are many similarities between DIT and the method of collision probabilities. DIT is in many cases faster, because for a certain accuracy in the fluxes DIT often needs fewer space points than the method of collision probabilities needs regions. Several computer codes using DIT, both one-group and multigroup, have been written. It is anticipated that experience gained in calculations with these codes will be reported in another paper.
Solitary Wave in One-dimensional Buckyball System at Nanoscale
Xu, Jun; Zheng, Bowen; Liu, Yilun
2016-01-01
We have studied the stress wave propagation in one-dimensional (1-D) nanoscopic buckyball (C60) system by molecular dynamics (MD) simulation and quantitative modeling. Simulation results have shown that solitary waves are generated and propagating in the buckyball system through impacting one buckyball at one end of the buckyball chain. We have found the solitary wave behaviors are closely dependent on the initial temperature and impacting speed of the buckyball chain. There are almost no dispersion and dissipation of the solitary waves (stationary solitary wave) for relatively low temperature and high impacting speed. While for relatively high temperature and low impacting speed the profile of the solitary waves is highly distorted and dissipated after propagating several tens of buckyballs. A phase diagram is proposed to describe the effect of the temperature and impacting speed on the solitary wave behaviors in buckyball system. In order to quantitatively describe the wave behavior in buckyball system, a simple nonlinear-spring model is established, which can describe the MD simulation results at low temperature very well. The results presented in this work may lay a solid step towards the further understanding and manipulation of stress wave propagation and impact energy mitigation at nanoscale. PMID:26891624
Correlation effects for a quasi-one-dimensional polaron gas
Energy Technology Data Exchange (ETDEWEB)
Machado, Paulo Cesar Miranda [Escola de Engenharia Eletrica e de Computacao, Universidade Federal de Goias, Goiania (Brazil); Borges, Antonio Newton; Osorio, Francisco Aparecido Pinto [Instituto de Fisica, Universidade Federal de Goias, Goiania (Brazil); Nucleo de Pesquisa em Fisica, Pontificia Universidade Catolica de Goias, Goiania (Brazil)
2011-04-15
In this work, we investigate the plasmon-LO phonon interaction effects on the intrasubband structure factor, electron-electron effective potential, and plasmon energy associated with the lowest subband in a GaAs-AlGaAs rectangular quantum-well wire (QWW) as a function of the electronic density. Our calculations are performed using the self-consistent field approximation, which includes the local-field correction (LFC) within the Singwi, Tosi, Land, and Sjolander (STLS) theory, at zero temperature and assuming a three-subband model, where only the first subband is occupied by electrons. We report for the first time dips in the structure factor spectra as a function of the quasi-one-dimensional (Q1D) plasmon-LO phonon wavevector that are directly related with the resonant split of the collective excitation energy into two branches due to the polaronic effects. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Solution-phase Synthesis of One-dimensional Semiconductor Nanostructures
Institute of Scientific and Technical Information of China (English)
Jianfeng YE; Limin QI
2008-01-01
The synthesis of one-dimensional (1D) semiconductor nanostructures has been studied intensively for a wide range of materials due to their unique structural and physical properties and promising potential for future technological applications. Among various strategies for synthesizing 1D semiconductor nanostructures, solution-phase synthetic routes are advantageous in terms of cost, throughput, modulation of composition, and the potential for large-scale and environmentally benign production. This article gives a concise review on the recent developments in the solution-phase synthesis of 1D semiconductor nanostructures of different compositions, sizes, shapes, and architectures. We first introduce several typical solution-phase synthetic routes based on controlled precipitation from homogeneous solutions, including hydrothermal/solvothermal process, solution-liquid-solid (SLS) process, high-temperature organic-solution process, and low-temperature aqueous-solution process. Subsequently, we discuss two solution-phase synthetic strategies involving solid templates or substrates, such as the chemical transformation of 1D sacrificial templates and the oriented growth of 1D nanostructure arrays on solid substrates. Finally, prospects of the solution-phase approaches to 1D semiconductor nanostructures will be briefly discussed.
Controlled Growth of One-Dimensional Oxide Nanomaterials
Institute of Scientific and Technical Information of China (English)
Xiaosheng FANG; Lide ZHANG
2006-01-01
This article reviews the recent developments in the controlled growth of one-dimensional (1D) oxide nanomaterials, including ZnO, SnO2, In2O3, Ga2O3, SiOx, MgO, and Al2O3. The growth of 1D oxide nanomaterials was carried out in a simple chemical vapor transport and condensation system. This article will begin with a survey of nanotechnology and 1D nanomaterials achieved by many researchers, and then mainly discuss on the controlled growth of 1D oxide nanomaterials with their morphologies, sizes, compositions, and microstructures controlled by altering experimental parameters, such as the temperature at the source material and the substrate, temperature gradient in the tube furnace, the total reaction time, the heating rate of the furnace, the gas flow rate, and the starting material. Their roles in the formation of various morphologies are analyzed and discussed. Finally, this review will be concluded with personal perspectives on the future research directions of this area.
Approximate Relativistic Solutions for One-Dimensional Cylindrical Coaxial Diode
Institute of Scientific and Technical Information of China (English)
曾正中; 刘国治; 邵浩
2002-01-01
Two approximate analytical relativistic solutions for one-dimensional, space-chargelimited cylindrical coaxial diode are derived and utilized to compose best-fitting approximate solutions. Comparison of the best-fitting solutions with the numerical one demonstrates an error of about 11% for cathode-inside arrangement and 12% in the cathode-outside case for ratios of larger to smaller electrode radius from 1.2 to 10 and a voltage above 0.5 MV up to 5 MV. With these solutions the diode lengths for critical self-magnetic bending and for the condition under which the parapotential model validates are calculated to be longer than 1 cm up to more than 100 cm depending on voltage, radial dimensions and electrode arrangement. The influence of ion flow from the anode on the relativistic electron-only solution is numerically computed, indicating an enhancement factor of total diode current of 1.85 to 4.19 related to voltage, radial dimension and electrode arrangement.
Negativity spectrum of one-dimensional conformal field theories
Ruggiero, Paola; Calabrese, Pasquale
2016-01-01
The partial transpose $\\rho_A^{T_2}$ of the reduced density matrix $\\rho_A$ is the key object to quantify the entanglement in mixed states, in particular through the presence of negative eigenvalues in its spectrum. Here we derive analytically the distribution of the eigenvalues of $\\rho_A^{T_2}$, that we dub negativity spectrum, in the ground sate of gapless one-dimensional systems described by a Conformal Field Theory (CFT), focusing on the case of two adjacent intervals. We show that the negativity spectrum is universal and depends only on the central charge of the CFT, similarly to the entanglement spectrum. The precise form of the negativity spectrum depends on whether the two intervals are in a pure or mixed state, and in both cases, a dependence on the sign of the eigenvalues is found. This dependence is weak for bulk eigenvalues, whereas it is strong at the spectrum edges. We also investigate the scaling of the smallest (negative) and largest (positive) eigenvalues of $\\rho_A^{T_2}$. We check our resu...
One-Dimensional Electron Transport Layers for Perovskite Solar Cells
Directory of Open Access Journals (Sweden)
Ujwal K. Thakur
2017-04-01
Full Text Available The electron diffusion length (Ln is smaller than the hole diffusion length (Lp in many halide perovskite semiconductors meaning that the use of ordered one-dimensional (1D structures such as nanowires (NWs and nanotubes (NTs as electron transport layers (ETLs is a promising method of achieving high performance halide perovskite solar cells (HPSCs. ETLs consisting of oriented and aligned NWs and NTs offer the potential not merely for improved directional charge transport but also for the enhanced absorption of incoming light and thermodynamically efficient management of photogenerated carrier populations. The ordered architecture of NW/NT arrays affords superior infiltration of a deposited material making them ideal for use in HPSCs. Photoconversion efficiencies (PCEs as high as 18% have been demonstrated for HPSCs using 1D ETLs. Despite the advantages of 1D ETLs, there are still challenges that need to be overcome to achieve even higher PCEs, such as better methods to eliminate or passivate surface traps, improved understanding of the hetero-interface and optimization of the morphology (i.e., length, diameter, and spacing of NWs/NTs. This review introduces the general considerations of ETLs for HPSCs, deposition techniques used, and the current research and challenges in the field of 1D ETLs for perovskite solar cells.
Digital noise generators using one-dimensional chaotic maps
Energy Technology Data Exchange (ETDEWEB)
Martínez-Ñonthe, J. A; Palacios-Luengas, L.; Cruz-Irisson, M.; Vazquez Medina, R. [Instituto Politécnico Nacional, ESIME-Culhuacan, Santa Ana 1000, 04430, D.F. (Mexico); Díaz Méndez, J. A. [Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Tonantzintla, Puebla (Mexico)
2014-05-15
This work shows how to improve the statistical distribution of signals produced by digital noise generators designed with one-dimensional (1-D) chaotic maps. It also shows that in a digital electronic design the piecewise linear chaotic maps (PWLCM) should be considered because they do not have stability islands in its chaotic behavior region, as it occurs in the case of the logistic map, which is commonly used to build noise generators. The design and implementation problems of the digital noise generators are analyzed and a solution is proposed. This solution relates the output of PWLCM, usually defined in the real numbers' domain, with a codebook of S elements, previously defined. The proposed solution scheme produces digital noise signals with a statistical distribution close to a uniform distribution. Finally, this work shows that it is possible to have control over the statistical distribution of the noise signal by selecting the control parameter of the PWLCM and using, as a design criterion, the bifurcation diagram.
Cooperative eigenmodes and scattering in one-dimensional atomic arrays
Bettles, Robert J.; Gardiner, Simon A.; Adams, Charles S.
2016-10-01
Collective coupling between dipoles can dramatically modify the optical response of a medium. Such effects depend strongly on the geometry of the medium and the polarization of the light. Using a classical coupled dipole model, here we investigate the simplest case of one-dimensional arrays of interacting atomic dipoles driven by a weak laser field. Changing the polarization and direction of the driving field allows us to separately address superradiant, subradiant, redshifted, and blueshifted eigenmodes, as well as observe strong Fano-like interferences between different modes. The cooperative eigenvectors can be characterized by the phase difference between nearest-neighbor dipoles, ranging from all oscillating in phase to all oscillating out of phase with their nearest neighbors. Investigating the eigenvalue behavior as a function of atom number and lattice spacing, we find that certain eigenmodes of an infinite atomic chain have the same decay rate as a single atom between two mirrors. The effects we observe provide a framework for collective control of the optical response of a medium, giving insight into the behavior of more complicated geometries, as well as providing further evidence for the dipolar analog of cavity QED.
One-Dimensional Electron Transport Layers for Perovskite Solar Cells
Thakur, Ujwal K.; Kisslinger, Ryan; Shankar, Karthik
2017-01-01
The electron diffusion length (Ln) is smaller than the hole diffusion length (Lp) in many halide perovskite semiconductors meaning that the use of ordered one-dimensional (1D) structures such as nanowires (NWs) and nanotubes (NTs) as electron transport layers (ETLs) is a promising method of achieving high performance halide perovskite solar cells (HPSCs). ETLs consisting of oriented and aligned NWs and NTs offer the potential not merely for improved directional charge transport but also for the enhanced absorption of incoming light and thermodynamically efficient management of photogenerated carrier populations. The ordered architecture of NW/NT arrays affords superior infiltration of a deposited material making them ideal for use in HPSCs. Photoconversion efficiencies (PCEs) as high as 18% have been demonstrated for HPSCs using 1D ETLs. Despite the advantages of 1D ETLs, there are still challenges that need to be overcome to achieve even higher PCEs, such as better methods to eliminate or passivate surface traps, improved understanding of the hetero-interface and optimization of the morphology (i.e., length, diameter, and spacing of NWs/NTs). This review introduces the general considerations of ETLs for HPSCs, deposition techniques used, and the current research and challenges in the field of 1D ETLs for perovskite solar cells. PMID:28468280
Nucleation and growth of nanoscaled one-dimensional materials
Cui, Hongtao
Nanoscaled one-dimensional materials have attracted great interest due to their novel physical and chemical properties. The purpose of this dissertation is to study the nucleation and growth mechanisms of carbon nanotubes and silicon nitride nanowires with their field emission applications in mind. As a result of this research, a novel methodology has been developed to deposit aligned bamboo-like carbon nanotubes on substrates using a methane and ammonia mixture in microwave plasma enhanced chemical deposition. Study of growth kinetics suggests that the carbon diffusion through bulk catalyst particles controls growth in the initial deposition process. Microstructures of carbon nanotubes are affected by the growth temperature and carbon concentration in the gas phase. High-resolution transmission electron microscope confirms the existence of the bamboo-like structure. Electron diffraction reveals that the iron-based catalyst nucleates and sustains the growth of carbon nanotubes. A nucleation and growth model has been constructed based upon experimental data and observations. In the study of silicon nitride nanoneedles, a vapor-liquid-solid model is employed to explain the nucleation and growth processes. Ammonia plasma etching is proposed to reduce the size of the catalyst and subsequently produce the novel needle-like nanostructure. High-resolution transmission electron microscope shows the structure is well crystallized and composed of alpha-silicon nitride. Other observations in the structure are also explained.
A disorder-enhanced quasi-one-dimensional superconductor.
Petrović, A P; Ansermet, D; Chernyshov, D; Hoesch, M; Salloum, D; Gougeon, P; Potel, M; Boeri, L; Panagopoulos, C
2016-01-01
A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2-δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials.
Spin interference in silicon one-dimensional rings
Energy Technology Data Exchange (ETDEWEB)
Bagraev, N T [Ioffe Physico-Technical Institute, RAS, 194021 St Petersburg (Russian Federation); Galkin, N G [Ioffe Physico-Technical Institute, RAS, 194021 St Petersburg (Russian Federation); Gehlhoff, W [Institut fuer Festkoerperphysik, TU Berlin, D-10623 Berlin (Germany); Klyachkin, L E [Ioffe Physico-Technical Institute, RAS, 194021 St Petersburg (Russian Federation); Malyarenko, A M [Ioffe Physico-Technical Institute, RAS, 194021 St Petersburg (Russian Federation); Shelykh, I A [Physics and Astronomy School, University of Southampton, Highfield, Southampton, S017 1BJ (United Kingdom)
2006-11-15
We present the first findings of the spin transistor effect in a Rashba gate-controlled ring embedded in a p-type self-assembled silicon quantum well that is prepared on an n-type Si(100) surface. The coherence and phase sensitivity of the spin-dependent transport of holes are studied by varying the values of the external magnetic field and the bias voltage that are applied perpendicularly to the plane of the double-slit ring. First, the amplitude and phase sensitivity of the 0.7 x (2e{sup 2}/h) feature of the hole quantum conductance staircase revealed by the quantum point contact inserted in one of the arms of the double-slit ring are found to result from the interplay of the spontaneous spin polarization and the Rashba spin-orbit interaction. Second, the quantum scatterers connected to two one-dimensional leads and the quantum point contact inserted are shown to define the amplitude and the phase of the Aharonov-Bohm and the Aharonov-Casher conductance oscillations. (letter to the editor)
Multi-symplectic, Lagrangian, one-dimensional gas dynamics
Webb, G. M.
2015-05-01
The equations of Lagrangian, ideal, one-dimensional, compressible gas dynamics are written in a multi-symplectic form using the Lagrangian mass coordinate m and time t as independent variables, and in which the Eulerian position of the fluid element x = x(m, t) is one of the dependent variables. This approach differs from the Eulerian, multi-symplectic approach using Clebsch variables. Lagrangian constraints are used to specify equations for xm, xt, and St consistent with the Lagrangian map, where S is the entropy of the gas. We require St = 0 corresponding to advection of the entropy S with the flow. We show that the Lagrangian Hamiltonian equations are related to the de Donder-Weyl multi-momentum formulation. The pullback conservation laws and the symplecticity conservation laws are discussed. The pullback conservation laws correspond to invariance of the action with respect to translations in time (energy conservation) and translations in m in Noether's theorem. The conservation law due to m-translation invariance gives rise to a novel nonlocal conservation law involving the Clebsch variable r used to impose ∂S(m, t)/∂t = 0. Translation invariance with respect to x in Noether's theorem is associated with momentum conservation. We obtain the Cartan-Poincaré form for the system, and use it to obtain a closed ideal of two-forms representing the equation system.
Phonons in a one-dimensional microfluidic crystal
Beatus, Tsevi; Bar-Ziv, Roy; 10.1038/nphys432
2010-01-01
The development of a general theoretical framework for describing the behaviour of a crystal driven far from equilibrium has proved difficult1. Microfluidic crystals, formed by the introduction of droplets of immiscible fluid into a liquid-filled channel, provide a convenient means to explore and develop models to describe non-equilibrium dynamics2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Owing to the fact that these systems operate at low Reynolds number (Re), in which viscous dissipation of energy dominates inertial effects, vibrations are expected to be over-damped and contribute little to their dynamics12, 13, 14. Against such expectations, we report the emergence of collective normal vibrational modes (equivalent to acoustic 'phonons') in a one-dimensional microfluidic crystal of water-in-oil droplets at Reapprox10-4. These phonons propagate at an ultra-low sound velocity of approx100 mum s-1 and frequencies of a few hertz, exhibit unusual dispersion relations markedly different to those of harmonic crystals, and g...
Conjugated Molecules Described by a One-Dimensional Dirac Equation.
Ernzerhof, Matthias; Goyer, Francois
2010-06-08
Starting from the Hückel Hamiltonian of conjugated hydrocarbon chains (ethylene, allyl radical, butadiene, pentadienyl radical, hexatriene, etc.), we perform a simple unitary transformation and obtain a Dirac matrix Hamiltonian. Thus already small molecules are described exactly in terms of a discrete Dirac equation, the continuum limit of which yields a one-dimensional Dirac Hamiltonian. Augmenting this Hamiltonian with specially adapted boundary conditions, we find that all the orbitals of the unsaturated hydrocarbon chains are reproduced by the continuous Dirac equation. However, only orbital energies close to the highest occupied molecular orbital/lowest unoccupied molecular orbital energy are accurately predicted by the Dirac equation. Since it is known that a continuous Dirac equation describes the electronic structure of graphene around the Fermi energy, our findings answer the question to what extent this peculiar electronic structure is already developed in small molecules containing a delocalized π-electron system. We illustrate how the electronic structure of small polyenes carries over to a certain class of rectangular graphene sheets and eventually to graphene itself. Thus the peculiar electronic structure of graphene extends to a large degree to the smallest unsaturated molecule (ethylene).
Validation and Comparison of One-Dimensional Graound Motion Methodologies
Energy Technology Data Exchange (ETDEWEB)
B. Darragh; W. Silva; N. Gregor
2006-06-28
Both point- and finite-source stochastic one-dimensional ground motion models, coupled to vertically propagating equivalent-linear shear-wave site response models are validated using an extensive set of strong motion data as part of the Yucca Mountain Project. The validation and comparison exercises are presented entirely in terms of 5% damped pseudo absolute response spectra. The study consists of a quantitative analyses involving modeling nineteen well-recorded earthquakes, M 5.6 to 7.4 at over 600 sites. The sites range in distance from about 1 to about 200 km in the western US (460 km for central-eastern US). In general, this validation demonstrates that the stochastic point- and finite-source models produce accurate predictions of strong ground motions over the range of 0 to 100 km and for magnitudes M 5.0 to 7.4. The stochastic finite-source model appears to be broadband, producing near zero bias from about 0.3 Hz (low frequency limit of the analyses) to the high frequency limit of the data (100 and 25 Hz for response and Fourier amplitude spectra, respectively).
Fermion Coherent State Studies of One-Dimensional Hubbard Model
Institute of Scientific and Technical Information of China (English)
LIN Ji; GAO Xian-Long; WANG Ke-Lin
2007-01-01
We present a comparative study of the ground state of the one-dimensional Hubbard model. We first use a new fermion coherent state method in the framework of Fermi liquid theory by introducing a hole operator and considering the interactions of two pairs electrons and holes. We construct the ground state of the Hubbard model as ｜〉 = [f + ∑′ψc+k1σ1 h+k2σ2 c+k3σ3 h+k4σ4 ∏exp(ρc+k1σ1 h+k2σ2)] [〉0, where ψ and ρ are the coupling constants. Our results are then compared to those of variational methods, density functional theory based on the exact solvable Bethe ansatz solutions, variational Monto-Carlo method (VMC) as well as to the exact result of the infinite system. We find satisfactory agreement between the fermion coherent state scheme and the VMC data, and provide a new picture to deal with the strongly correlated system.
Charge transport through one-dimensional Moiré crystals.
Bonnet, Roméo; Lherbier, Aurélien; Barraud, Clément; Della Rocca, Maria Luisa; Lafarge, Philippe; Charlier, Jean-Christophe
2016-01-20
Moiré superlattices were generated in two-dimensional (2D) van der Waals heterostructures and have revealed intriguing electronic structures. The appearance of mini-Dirac cones within the conduction and valence bands of graphene is one of the most striking among the new quantum features. A Moiré superstructure emerges when at least two periodic sub-structures superimpose. 2D Moiré patterns have been particularly investigated in stacked hexagonal 2D atomic lattices like twisted graphene layers and graphene deposited on hexagonal boron-nitride. In this letter, we report both experimentally and theoretically evidence of superlattices physics in transport properties of one-dimensional (1D) Moiré crystals. Rolling-up few layers of graphene to form a multiwall carbon nanotube adds boundaries conditions that can be translated into interference fringes-like Moiré patterns along the circumference of the cylinder. Such a 1D Moiré crystal exhibits a complex 1D multiple bands structure with clear and robust interband quantum transitions due to the presence of mini-Dirac points and pseudo-gaps. Our devices consist in a very large diameter (>80 nm) multiwall carbon nanotubes of high quality, electrically connected by metallic electrodes acting as charge reservoirs. Conductance measurements reveal the presence of van Hove singularities assigned to 1D Moiré superlattice effect and illustrated by electronic structure calculations.
Redshift distortions in one-dimensional power spectra
Desjacques, V; Desjacques, Vincent; Nusser, Adi
2004-01-01
We present a model for one-dimensional (1D) matter power spectra in redshift space as estimated from data provided along individual lines of sight. We derive analytic expressions for these power spectra in the linear and nonlinear regimes, focusing on redshift distortions arising from peculiar velocities. In the linear regime, redshift distortions enhance the 1D power spectra only on small scales, and do not affect the power on large scales. This is in contrast to the effect of distortions on three-dimensional (3D) power spectra estimated from data in 3D space, where the enhancement is independent of scale. For CDM cosmologies, the 1D power spectra in redshift and real space are similar for wavenumbers $q<0.1h/Mpc$ where both have a spectral index close to unity, independent of the details of the 3D power spectrum. Nonlinear corrections drive the 1D power spectrum in redshift space into a nearly universal shape over scale $q<10h/Mpc$, and suppress the power on small scales as a result of the strong velo...
Electron Rydberg wave packets in one-dimensional atoms
Indian Academy of Sciences (India)
Supriya Chatterjee; Amitava Choudhuri; Aparna Saha; B Talukdar
2010-09-01
An expression for the transition probability or form factor in one-dimensional Rydberg atom irradiated by short half-cycle pulse was constructed. In applicative contexts, our expression was found to be more useful than the corresponding result given by Landau and Lifshitz. Using the new expression for the form factor, the motion of a localized quantum wave packet was studied with particular emphasis on its revival and super-revival properties. Closed form analytical expressions were derived for expectation values of the position and momentum operators that characterized the widths of the position and momentum distributions. Transient phase-space localization of the wave packet produced by the application of a single impulsive kick was explicitly demonstrated. The undulation of the uncertainty product as a function of time was studied in order to visualize how the motion of the wave packet in its classical trajectory spreads throughout the orbit and the system becomes nonclassical. The process, however, repeats itself such that the atom undergoes a free evolution from a classical, to a nonclassical, and back to a classical state.
One-dimensional Ising model with multispin interactions
Turban, L
2016-01-01
We study the spin-$1/2$ Ising chain with multispin interactions $K$ involving the product of $m$ successive spins, for general values of $m$. Using a change of spin variables the zero-field partition function of a finite chain is obtained for free and periodic boundary conditions (BC) and we calculate the two-spin correlation function. When placed in an external field $H$ the system is shown to be self-dual. Using another change of spin variables the one-dimensional (1D) Ising model with multispin interactions in a field is mapped onto a zero-field rectangular Ising model with first-neighbour interactions $K$ and $H$. The 2D system, with size $m\\times N/m$, has the topology of a cylinder with helical BC. In the thermodynamic limit $N/m\\to\\infty$, $m\\to\\infty$, a 2D critical singularity develops on the self-duality line, $\\sinh 2K\\sinh 2H=1$.
One dimensional numerical simulation of small scale CFB combustors
Energy Technology Data Exchange (ETDEWEB)
Gungor, Afsin [Department of Mechanical Engineering, Faculty of Engineering and Architecture, Nigde University, 51100 Nigde (Turkey)
2009-03-15
In this study, a one-dimensional model which includes volatilization, attrition and combustion of char particles for a circulating fluidized bed (CFB) combustor has been developed. In the modeling, the CFB combustor is analyzed in two regions: bottom zone considering as a bubbling fluidized bed in turbulent fluidization regime and upper zone core-annulus solids flow structure is established. In the bottom zone, a single-phase back-flow cell model is used to represent the solid mixing. Solids exchange, between the bubble phase and emulsion phase is a function of the bubble diameter and varies along the axis of the combustor. In the upper zone, particles move upward in the core and downward in the annulus. Thickness of the annulus varies according to the combustor height. Using the developed simulation program, the effects of operational parameters which are the particle diameter, superficial velocity and air-to-fuel ratio on net solids flux, oxygen and carbon dioxide mole ratios along the bed height and carbon content and bed temperature on the top of the riser are investigated. Simulation results are compared with test results obtained from the 50 kW Gazi University Heat Power Laboratory pilot scale unit and good agreement is observed. (author)
One dimensional coordination polymers: Synthesis, crystal structures and spectroscopic properties
Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Şahin, Onur
2016-11-01
Two new one dimensional (1D) cyanide complexes, namely [M(4-aepy)2(H2O)2][Pt(CN)4], (4-aepy = 4-(2-aminoethyl)pyridine M = Cu(II) (1) or Zn(II) (2)), have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal and elemental analyses techniques. The crystallographic analyses reveal that 1 and 2 are isomorphous and isostructural, and crystallize in the monoclinic system and C2 space group. The Pt(II) ions are coordinated by four cyanide-carbon atoms in the square-planar geometry and the [Pt(CN)4]2- ions act as a counter ion. The M(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4-aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. The crystal structures of 1 and 2 are similar each other and linked via intermolecular hydrogen bonding, Pt⋯π interactions to form 3D supramolecular network. Vibration assignments of all the observed bands are given and the spectral features also supported to the crystal structures of the complexes.
Automated quantification of one-dimensional nanostructure alignment on surfaces
Dong, Jianjin; Goldthorpe, Irene A.; Mohieddin Abukhdeir, Nasser
2016-06-01
A method for automated quantification of the alignment of one-dimensional (1D) nanostructures from microscopy imaging is presented. Nanostructure alignment metrics are formulated and shown to be able to rigorously quantify the orientational order of nanostructures within a two-dimensional domain (surface). A complementary image processing method is also presented which enables robust processing of microscopy images where overlapping nanostructures might be present. Scanning electron microscopy (SEM) images of nanowire-covered surfaces are analyzed using the presented methods and it is shown that past single parameter alignment metrics are insufficient for highly aligned domains. Through the use of multiple parameter alignment metrics, automated quantitative analysis of SEM images is shown to be possible and the alignment characteristics of different samples are able to be quantitatively compared using a similarity metric. The results of this work provide researchers in nanoscience and nanotechnology with a rigorous method for the determination of structure/property relationships, where alignment of 1D nanostructures is significant.
Stepwise Nanopore Evolution in One-Dimensional Nanostructures
Choi, Jang Wook
2010-04-14
We report that established simple lithium (Li) ion battery cycles can be used to produce nanopores inside various useful one-dimensional (1D) nanostructures such as zinc oxide, silicon, and silver nanowires. Moreover, porosities of these 1D nanomaterials can be controlled in a stepwise manner by the number of Li-battery cycles. Subsequent pore characterization at the end of each cycle allows us to obtain detailed snapshots of the distinct pore evolution properties in each material due to their different atomic diffusion rates and types of chemical bonds. Also, this stepwise characterization led us to the first observation of pore size increases during cycling, which can be interpreted as a similar phenomenon to Ostwald ripening in analogous nanoparticle cases. Finally, we take advantage of the unique combination of nanoporosity and 1D materials and demonstrate nanoporous silicon nanowires (poSiNWs) as excellent supercapacitor (SC) electrodes in high power operations compared to existing devices with activated carbon. © 2010 American Chemical Society.
A one-dimensional theory for Higgs branch operators
Dedushenko, Mykola; Yacoby, Ran
2016-01-01
We use supersymmetric localization to calculate correlation functions of half-BPS local operators in 3d ${\\cal N} = 4$ superconformal field theories whose Lagrangian descriptions consist of vectormultiplets coupled to hypermultiplets. The operators we primarily study are certain twisted linear combinations of Higgs branch operators that can be inserted anywhere along a given line. These operators are constructed from the hypermultiplet scalars. They form a one-dimensional non-commutative operator algebra with topological correlation functions. The 2- and 3-point functions of Higgs branch operators in the full 3d ${\\cal N}=4$ theory can be simply inferred from the 1d topological algebra. After conformally mapping the 3d superconformal field theory from flat space to a round three-sphere, we preform supersymmetric localization using a supercharge that does not belong to any 3d ${\\cal N} = 2$ subalgebra of the ${\\cal N}=4$ algebra. The result is a simple model that can be used to calculate correlation functions ...
Synthesis and application of one-dimensional nanomaterials
Zhang, Daihua
My research has been focused on the synthesis, characterization and application of three types of one-dimensional (1D) nanostructures, including metal oxide nanowires, transition metal oxide core-shell nanocables, and carbon nanotubes. They represent a new class of materials that have attracted steadily growing interest due to their peculiar properties and unique applications complementary to bulk materials. This dissertation will summarize my studies on these three 1D nanomaterials, as well as propose future research work that may lead to further development of this field. Following a brief introduction to 1D nanomaterials in Chapter 1, Chapter 2 will focus on the first material - metal oxide nanowires. The discussion starts from the synthesis approach and material characterization of metal oxide nanowires, and then shifts to the electron transport properties and potential applications. A series of functional devices based on In2O 3 and SnO2 nanowires will be demonstrated and evaluated, which range from field effect transistors (FETs), nonvolatile memories, to photo-detecting devices and chemical sensors. Chapter 3 will discuss the fabrication of transition metal oxide (TMO) core-shell nanocables and their electron transport properties as a function of temperature and external magnetic field. The discussion will primarily focus on one of the TMO materials---magnetite (Fe3O 4) core-shell nanowires and nanotubes. Chapter 4 focuses on the application of carbon nanotubes (CNTs) in macroelectronics and explores the feasibility of using CNT films as transparent electrodes for organic light emitting diodes (OLEDs). Chapter 5, in the end, summarizes the above discussions and proposes future research directions in 1D nanomaterials.
One-dimensional semirelativistic Hamiltonian with multiple Dirac delta potentials
Erman, Fatih; Gadella, Manuel; Uncu, Haydar
2017-02-01
In this paper, we consider the one-dimensional semirelativistic Schrödinger equation for a particle interacting with N Dirac delta potentials. Using the heat kernel techniques, we establish a resolvent formula in terms of an N ×N matrix, called the principal matrix. This matrix essentially includes all the information about the spectrum of the problem. We study the bound state spectrum by working out the eigenvalues of the principal matrix. With the help of the Feynman-Hellmann theorem, we analyze how the bound state energies change with respect to the parameters in the model. We also prove that there are at most N bound states and explicitly derive the bound state wave function. The bound state problem for the two-center case is particularly investigated. We show that the ground state energy is bounded below, and there exists a self-adjoint Hamiltonian associated with the resolvent formula. Moreover, we prove that the ground state is nondegenerate. The scattering problem for N centers is analyzed by exactly solving the semirelativistic Lippmann-Schwinger equation. The reflection and the transmission coefficients are numerically and asymptotically computed for the two-center case. We observe the so-called threshold anomaly for two symmetrically located centers. The semirelativistic version of the Kronig-Penney model is shortly discussed, and the band gap structure of the spectrum is illustrated. The bound state and scattering problems in the massless case are also discussed. Furthermore, the reflection and the transmission coefficients for the two delta potentials in this particular case are analytically found. Finally, we solve the renormalization group equations and compute the beta function nonperturbatively.
Filtration-guided assembly for patterning one-dimensional nanostructures
Zhang, Yaozhong; Wang, Chuan; Yeom, Junghoon
2017-04-01
Tremendous progress has been made in synthesizing various types of one-dimensional (1D) nanostructures (NSs), such as nanotubes and nanowires, but some technical challenges still remain in the deterministic assembly of the solution-processed 1D NSs for device integration. In this work we investigate a scalable yet inexpensive nanomaterial assembly method, namely filtration-guided assembly (FGA), to place nanomaterials into desired locations as either an individual entity or ensembles, and form functional devices. FGA not only addresses the assembly challenges but also encompasses the notion of green nanomanufacturing, maximally utilizing nanomaterials and eliminating a waste stream of nanomaterials into the environment. FGA utilizes selective filtration of 1D NSs through the open windows on the nanoporous filter membrane whose surface is patterned by a polymer mask for guiding the 1D NS deposition. The modified soft-lithographic technique called blanket transfer (BT) is employed to create the various photoresist patterns of sub-10-micron resolution on the nanoporous filter membrane like mixed cellulose acetate. We use single-walled carbon nanotubes (SWCNTs) as a model 1D NS and demonstrate the fabrication of an array pattern of homogeneous 1D NS network films over an area of 20 cm2 within 10 min. The FGA-patterned SWCNT network films are transferred onto the substrate using the adhesive-based transfer technique, and show the highly uniform film thickness and resistance measurements across the entire substrate. Finally, the electrical performance of the back-gated transistors made from the FGA and transfer method of 95% pure SWCNTs is demonstrated.
Spatial modes in one-dimensional models for capillary jets
Guerrero, J.; González, H.; García, F. J.
2016-03-01
One-dimensional (1D) models are widely employed to simplify the analysis of axisymmetric capillary jets. These models postulate that, for slender deformations of the free surface, the radial profile of the axial velocity can be approximated as uniform (viscous slice, averaged, and Cosserat models) or parabolic (parabolic model). In classical works on spatial stability analysis with 1D models, considerable misinterpretation was generated about the modes yielded by each model. The already existing physical analysis of three-dimensional (3D) axisymmetric spatial modes enables us to relate these 1D spatial modes to the exact 3D counterparts. To do so, we address the surface stimulation problem, which can be treated as linear, by considering the effect of normal and tangential stresses to perturb the jet. A Green's function for a spatially local stimulation having a harmonic time dependence provides the general formalism to describe any time-periodic stimulation. The Green's function of this signaling problem is known to be a superposition of the spatial modes, but in fact these modes are of fundamental nature, i.e., not restricted to the surface stimulation problem. The smallness of the wave number associated with each mode is the criterion to validate or invalidate the 1D approaches. The proposed axial-velocity profiles (planar or parabolic) also have a remarkable influence on the outcomes of each 1D model. We also compare with the classical 3D results for (i) conditions for absolute instability, and (ii) the amplitude of the unstable mode resulting from both normal and tangential surface stress stimulation. Incidentally, as a previous task, we need to re-deduce 1D models in order to include eventual stresses of various possible origins (electrohydrodynamic, thermocapillary, etc.) applied on the free surface, which were not considered in the previous general formulations.
Rashba electron transport in one-dimensional quantum waveguides
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The properties of Rashba wave function in the planar one-dimensional waveguide are studied, and the following results are obtained. Due to the Rashba effect, the plane waves of electron with the energy E divide into two kinds of waves with the wave vectors k 1 =k 0 +k δ and k 2 =k 0 -k δ , where k δ is proportional to the Rashba coefficient, and their spin orientations are +π/2 (spin up) and -π/2 (spin down) with respect to the circuit, respectively. If there is gate or ferromagnetic contact in the circuit, the Rashba wave function becomes standing wave form exp(±ik δ l)sin[k 0 (l-L)], where L is the position coordinate of the gate or contact. Unlike the electron without considering the spin, the phase of the Rashba plane or standing wave function depends on the direction angle θ of the circuit. The travel velocity of the Rashba waves with the wave vector k 1 or k 2 are the same hk0/m * . The boundary conditions of the Rashba wave functions at the intersection of circuits are given from the continuity of wave functions and the conservation of current density. Using the boundary conditions of Rashba wave functions we study the transmission and reflection probabilities of Rashba electron moving in several structures, and find the interference effects of the two Rashba waves with different wave vectors caused by ferromagnetic contact or the gate. Lastly we derive the general theory of multiple branches structure. The theory can be used to design various spin polarized devices.
Hardening transition in a one-dimensional model for ferrogels
Annunziata, Mario Alberto; Menzel, Andreas M.; Löwen, Hartmut
2013-05-01
We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance.
Fractal spectra in generalized Fibonacci one-dimensional magnonic quasicrystals
Energy Technology Data Exchange (ETDEWEB)
Costa, C.H.O. [Departamento de Fisica Teorica e Experimental, Universidade Federal do Rio grande do Norte, 59072-970 Natal-RN (Brazil); Vasconcelos, M.S., E-mail: manoelvasconcelos@yahoo.com.br [Escola de Ciencias e Tecnologia, Universidade Federal do Rio grande do Norte, 59072-970 Natal-RN (Brazil); Barbosa, P.H.R.; Barbosa Filho, F.F. [Departamento de Fisica, Universidade Federal do Piaui, 64049-550 Teresina-Pi (Brazil)
2012-07-15
In this work we carry out a theoretical analysis of the spectra of magnons in quasiperiodic magnonic crystals arranged in accordance with generalized Fibonacci sequences in the exchange regime, by using a model based on a transfer-matrix method together random-phase approximation (RPA). The generalized Fibonacci sequences are characterized by an irrational parameter {sigma}(p,q), which rules the physical properties of the system. We discussed the magnonic fractal spectra for first three generalizations, i.e., silver, bronze and nickel mean. By varying the generation number, we have found that the fragmentation process of allowed bands makes possible the emergence of new allowed magnonic bulk bands in spectra regions that were magnonic band gaps before, such as which occurs in doped semiconductor devices. This interesting property arises in one-dimensional magnonic quasicrystals fabricated in accordance to quasiperiodic sequences, without the need to introduce some deferent atomic layer or defect in the system. We also make a qualitative and quantitative investigations on these magnonic spectra by analyzing the distribution and magnitude of allowed bulk bands in function of the generalized Fibonacci number F{sub n} and as well as how they scale as a function of the number of generations of the sequences, respectively. - Highlights: Black-Right-Pointing-Pointer Quasiperiodic magnonic crystals are arranged in accordance with the generalized Fibonacci sequence. Black-Right-Pointing-Pointer Heisenberg model in exchange regime is applied. Black-Right-Pointing-Pointer We use a theoretical model based on a transfer-matrix method together random-phase approximation. Black-Right-Pointing-Pointer Fractal spectra are characterized. Black-Right-Pointing-Pointer We analyze the distribution of allowed bulk bands in function of the generalized Fibonacci number.
Trabelsi, Youssef; Benali, Naim; Bouazzi, Yassine; Kanzari, Mounir
2013-09-01
The transmission properties of hybrid quasi-periodic photonic systems (HQPS) made by the combination of one-dimensional periodic photonic crystals (PPCs) and quasi-periodic photonic crystals (QPCs) were theoretically studied. The hybrid quasi-periodic photonic lattice based on the hetero-structures was built from the Fibonacci and Thue-Morse sequences. We addressed the microwave properties of waves through the one-dimensional symmetric Fibonacci, and Thue-Morse system i.e., a quasi-periodic structure was made up of two different dielectric materials (Rogers and air), in the quarter wavelength condition. It shows that controlling the Fibonacci parameters permits to obtain selective optical filters with the narrow passband and polychromatic stop band filters with varied properties which can be controlled as desired. From the results, we presented the self-similar features of the spectra, and we also presented the fractal process through a return map of the transmission coefficients. We extracted powerfully the band gaps of hybrid quasi-periodic multilayered structures, called "pseudo band gaps", often containing resonant states, which could be considered as a manifestation of numerous defects distributed along the structure. The results of transmittance spectra showed that the cutoff frequency could be manipulated through the thicknesses of the defects and the type of dielectric layers of the system. Taken together, the above two properties provide favorable conditions for the design of an all-microwave intermediate reflector.
Institute of Scientific and Technical Information of China (English)
S. PRASAD; Vivek SINGH; A. K. SINGH
2012-01-01
An analytical study is presented on the modal dispersion characteristics, group velocity, and effective group, as well as the phase index of a ternary one dimensional plasma photonic crystal for an obliquely incident electromagnetic wave considering the effect of collisions in plasma layers. The dispersion relation is derived by using the transfer matrix method and the boundary conditions based on electromagnetic theory. The dispersion curves are plotted for both the normal photonic band gap structure and the absorption photonic band gap structure. It is found that the increase in the angle of incidence shifts the photonic band gap toward higher frequencies. Also, the cutoff frequency is independent of collisions.
Strong correlations and topological order in one-dimensional systems
De Gottardi, Wade Wells
This thesis presents theoretical studies of strongly correlated systems as well as topologically ordered systems in 1D. Non-Fermi liquid behavior characteristic of interacting 1D electron systems is investigated with an emphasis on experimentally relevant setups and observables. The existence of end Majorana fermions in a 1D p-wave superconductor subject to periodic, incommensurate and disordered potentials is studied. The Tomonaga-Luttinger liquid (TLL), a model of interacting electrons in one spatial dimension, is considered in the context of two systems of experimental interest. First, a study of the electronic properties of single-walled armchair carbon nanotubes in the presence of transverse electric and magnetic fields is presented. As a result of their effect on the band structure and electron wave functions, fields alter the nature of the (effective) Coulomb interaction in tubes. In particular, it is found that fields couple to nanotube bands (or valleys), a quantum degree of freedom inherited from the underlying graphene lattice. As revealed by a detailed TLL calculation, it is predicted that fields induce electrons to disperse into their spin, band, and charge components. Fields also provide a means of tuning the shell-filling behavior associated with short tubes. The phenomenon of charge fractionalization is investigated in a one-dimensional ring. TLL theory predicts that momentum-resolved electrons injected into the ring will fractionalize into clockwise- and counterclockwise-moving quasiparticles. As a complement to transport measurements in quantum wires connected to leads, non-invasive measures involving the magnetic field profiles around the ring are proposed. Topological aspects of 1D p-wave superconductors are explored. The intimate connection between non-trivial topology (fermions) and spontaneous symmetry breaking (spins) in one-dimension is investigated. Building on this connection, a spin ladder system endowed with vortex degrees of freedom is
Energy Technology Data Exchange (ETDEWEB)
Luna-Acosta, G.A. [Instituto de Fisica, Universidad Autonoma de Puebla, Apartado Postal J-48, Puebla, Pue., 72570 (Mexico); Makarov, N.M. [Instituto de Ciencias, Universidad Autonoma de Puebla, Priv. 17 Norte No 3417, Col. San Miguel Hueyotlipan, Puebla, Pue., 72050 (Mexico)
2009-12-15
We study numerically and analytically the role of Fabry-Perot resonances in the transmission through a one-dimensional finite array formed by two alternating dielectric slabs. The disorder consists in varying randomly the width of one type of layers while keeping constant the width of the other type. Our numerical simulations show that localization is strongly inhibited in a wide neighborhood of the Fabry-Perot resonances. Comparison of our numerical results with an analytical expression for the average transmission, derived for weak disorder and finite number of cells, reveals that such expression works well even for medium disorder up to a certain frequency. Our results are valid for photonic and phononic one-dimensional disordered crystals, as well as for semiconductor superlattices. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
Hua, Ming; Tao, Ming-Jie; Deng, Fu-Guo
2016-02-24
We propose a quantum processor for the scalable quantum computation on microwave photons in distant one-dimensional superconducting resonators. It is composed of a common resonator R acting as a quantum bus and some distant resonators rj coupled to the bus in different positions assisted by superconducting quantum interferometer devices (SQUID), different from previous processors. R is coupled to one transmon qutrit, and the coupling strengths between rj and R can be fully tuned by the external flux through the SQUID. To show the processor can be used to achieve universal quantum computation effectively, we present a scheme to complete the high-fidelity quantum state transfer between two distant microwave-photon resonators and another one for the high-fidelity controlled-phase gate on them. By using the technique for catching and releasing the microwave photons from resonators, our processor may play an important role in quantum communication as well.
Salem, Mohamed Shaker; Ibrahim, Shaimaa Moustafa; Amin, Mohamed
2017-07-01
A novel silicon-based optical microcavity composed of a defect layer sandwiched between two parallel rugate mirrors is created by the electrochemical anodization of silicon in a hydrofluoric acid-based electrolyte using a precisely controlled current density profile. The profile consists of two sinusoidally modulated current waveforms separated by a fixed current that is applied to produce a defect layer between the mirrors. The spectral response of the rugate-based microcavity is simulated using the transfer matrix method and compared to the conventional Bragg-based microcavity. It is found that the resonance position of both microcavities is unchanged. However, the rugate-based microcavity exhibits a distinct reduction of the sidebands' intensity. Further attenuation of the sidebands' intensity is obtained by creating refractive index matching layers with optimized thickness at the bottom and top of the rugate-based microcavity. In order to stabilize the produced microcavity against natural oxidation, atomic layer deposition of an ultra-thin titanium dioxide layer on the pore wall is carried out followed by thermal annealing. The microcavity resonance position shows an observable sensitivity to the deposition and annealing processes.
Nonlinear Response of One-Dimensional Magneto-Optical Photonic Crystals
Institute of Scientific and Technical Information of China (English)
WANG Wei-Zhong
2005-01-01
@@ We numerically investigate the magneto-optical Cotton-Mouton effect in an alternating multilayer structure with a nonlinear dielectric constant. The multistability and polarization of the transmission of electromagnetic field near the edges of the stop gap are studied in detail. The resonant transmission is accompanied by solitons of intensity of the field. This investigation provides a way to select the transmission property with different polarizations since both the amplitude and the phase of the output field can be adjusted by the input power and by the magneto-optical coefficient depending on the external magnetic field.
Lime Kiln Modeling. CFD and One-dimensional simulations
Energy Technology Data Exchange (ETDEWEB)
Svedin, Kristoffer; Ivarsson, Christofer; Lundborg, Rickard
2009-03-15
The incentives for burning alternative fuels in lime kilns are growing. An increasing demand on thorough investigations of alternative fuel impact on lime kiln performance have been recognized, and the purpose of this project has been to develop a lime kiln CFD model with the possibility to fire fuel oil and lignin. The second part of the project consists of three technical studies. Simulated data from a one-dimensional steady state program has been used to support theories on the impact of biofuels and lime mud dryness. The CFD simulations was carried out in the commercial code FLUENT. Due to difficulties with the convergence of the model the calcination reaction is not included. The model shows essential differences between the two fuels. Lignin gives a different flame shape and a longer flame length compared to fuel oil. Mainly this depends on how the fuel is fed into the combustion chamber and how much combustion air that is added as primary and secondary air. In the case of lignin combustion the required amount of air is more than in the fuel oil case. This generates more combustion gas and a different flow pattern is created. Based on the values from turbulent reaction rate for the different fuels an estimated flame length can be obtained. For fuel oil the combustion is very intense with a sharp peak in the beginning and a rapid decrease. For lignin the combustion starts not as intense as for the fuel oil case and has a smoother shape. The flame length appears to be approximately 2-3 meter longer for lignin than for fuel oil based on turbulent reaction rate in the computational simulations. The first technical study showed that there are many benefits of increasing dry solids content in the lime mud going into a kiln such as increased energy efficiency, reduced TRS, and reduced sodium in the kiln. However, data from operating kilns indicates that these benefits can be offset by increasing exit gas temperature that can limit kiln production capacity. Simulated
Fabrication and characterization of one dimensional zinc oxide nanostructures
Cheng, Chun
In this thesis, one dimensional (1D) ZnO nanostructures with controlled morphologies, defects and alignment have been fabricated by a simple vapor transfer method. The crystal structures, interfaces, growth mechanisms and optical properties of ZnO nanostructures have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Great efforts have been devoted to the patterned growth and assembly of ZnO nanostructures as well as the stability of ZnO nanowires (NWs). Using carbonized photoresists, a simple and very effective method has been developed for fabricating and patterning high-quality ZnO NW arrays. ZnO NWs from this method show excellent alignment, crystal quality, and optical properties that are independent of the substrates. The carbonized photoresists provide perfect nucleation sites for the growth of aligned ZnO NWs and also perfectly connect to the NWs to form ideal electrodes. This approach is further extended to realize large area growth of different forms of ZnO NW arrays (e.g., the horizontal growth and multilayered ZnO NW arrays) on other kinds of carbon-based materials. In addition, the as-synthesized vertically aligned ZnO NW arrays show a low weighted reflectance (Rw) and can be used as antireflection coatings. Moreover, non c-axis growth of 1D ZnO nanostructures (e.g., nanochains, nanobrushes and nanobelts) and defect related 1D ZnO nanostructures (e.g., Y-shaped twinned nanobelts and hierarchical nanostructures decorated by flowers induced by screw dislocations) is also present. Using direct oxidization of pure Zn at high temperatures in air, uniformed ZnO NWs and tetrapods have been fabricated. The spatially-resolved PL study on these two kinds of nanostructures suggests that the defects leading to the green luminescence (GL) should originate from the structural changes along the legs of the tetrapods. Surface defects in these ZnO nanostructures play an unimportant
Lime Kiln Modeling. CFD and One-dimensional simulations
Energy Technology Data Exchange (ETDEWEB)
Svedin, Kristoffer; Ivarsson, Christofer; Lundborg, Rickard
2009-03-15
The incentives for burning alternative fuels in lime kilns are growing. An increasing demand on thorough investigations of alternative fuel impact on lime kiln performance have been recognized, and the purpose of this project has been to develop a lime kiln CFD model with the possibility to fire fuel oil and lignin. The second part of the project consists of three technical studies. Simulated data from a one-dimensional steady state program has been used to support theories on the impact of biofuels and lime mud dryness. The CFD simulations was carried out in the commercial code FLUENT. Due to difficulties with the convergence of the model the calcination reaction is not included. The model shows essential differences between the two fuels. Lignin gives a different flame shape and a longer flame length compared to fuel oil. Mainly this depends on how the fuel is fed into the combustion chamber and how much combustion air that is added as primary and secondary air. In the case of lignin combustion the required amount of air is more than in the fuel oil case. This generates more combustion gas and a different flow pattern is created. Based on the values from turbulent reaction rate for the different fuels an estimated flame length can be obtained. For fuel oil the combustion is very intense with a sharp peak in the beginning and a rapid decrease. For lignin the combustion starts not as intense as for the fuel oil case and has a smoother shape. The flame length appears to be approximately 2-3 meter longer for lignin than for fuel oil based on turbulent reaction rate in the computational simulations. The first technical study showed that there are many benefits of increasing dry solids content in the lime mud going into a kiln such as increased energy efficiency, reduced TRS, and reduced sodium in the kiln. However, data from operating kilns indicates that these benefits can be offset by increasing exit gas temperature that can limit kiln production capacity. Simulated
Ultra-high Q one-dimensional hybrid PhC-SPP waveguide microcavity with large structure tolerance
Liu, Feng; Zhang, Lingxuan; Lu, Xiaoyuan; Wang, Weiqiang; Wang, Leiran; Wang, Guoxi; Zhang, Wenfu; Zhao, Wei
2016-07-01
A photonic crystal - surface plasmon-polaritons hybrid transverse magnetic mode waveguide based on a one-dimensional optical microcavity is designed to work in the communication band. A Gaussian field distribution in a stepping heterojunction taper is designed by band engineering, and a silica layer compresses the mode field to the subwavelength scale. The designed microcavity possesses a resonant mode with a quality factor of 1609 and a modal volume of 0.01 cubic wavelength. The constant period and the large structure tolerance make it realizable by current processing techniques.
One-dimensional carbon nanostructures for terahertz electron-beam radiation
Tantiwanichapan, Khwanchai; Swan, Anna K.; Paiella, Roberto
2016-06-01
One-dimensional carbon nanostructures such as nanotubes and nanoribbons can feature near-ballistic electronic transport over micron-scale distances even at room temperature. As a result, these materials provide a uniquely suited solid-state platform for radiation mechanisms that so far have been the exclusive domain of electron beams in vacuum. Here we consider the generation of terahertz light based on two such mechanisms, namely, the emission of cyclotronlike radiation in a sinusoidally corrugated nanowire (where periodic angular motion is produced by the mechanical corrugation rather than an externally applied magnetic field), and the Smith-Purcell effect in a rectilinear nanowire over a dielectric grating. In both cases, the radiation properties of the individual charge carriers are investigated via full-wave electrodynamic simulations, including dephasing effects caused by carrier collisions. The overall light output is then computed with a standard model of charge transport for two particularly suitable types of carbon nanostructures, i.e., zigzag graphene nanoribbons and armchair single-wall nanotubes. Relatively sharp emission peaks at geometrically tunable terahertz frequencies are obtained in each case. The corresponding output powers are experimentally accessible even with individual nanowires, and can be scaled to technologically significant levels using array configurations. These radiation mechanisms therefore represent a promising paradigm for light emission in condensed matter, which may find important applications in nanoelectronics and terahertz photonics.
Analysis of polarized pulse propagation through one-dimensional scattering medium
Zhang, Yong; Yao, Feng-Ju; Xie, Ming; Yi, Hong-Liang
2017-08-01
This paper analyzes the polarized light propagation in a one-dimensional scattering medium with the upper surface subjected to an oblique incident short-pulsed laser beam using the natural element method (NEM). The NEM discretization scheme for the transient vector radiative transfer equation (TVRTE) is presented in detail. The accuracy of the natural element method for transient vector radiative transfer in the scattering medium is assessed. Numerical results show that the NEM is accurate, and effective in solving transient polarized radiative problems. We examine a square short-pulsed laser transport firstly in the atmosphere with Mie scattering and then within aerosol scattering medium. We then investigate the transient polarized radiative transfer problem in the atmosphere-ocean system. The time-resolved signals and the polarization state of the Stokes vector are presented and analyzed. It is found that the scattering types of the medium make greatly influence on the transient transportation of the polarized light. Critically, the polarization states of the backward and forward scattered photons show significantly different time varying trends. For the two-layer system with dissimilar refractive index distributions, due to the total-reflection effect, the existence of a Fresnel interface significantly changes the polarization state of the light, and discontinuous distribution features are observed on the interface.
Belopolski, Ilya; Xu, Su-Yang; Koirala, Nikesh; Liu, Chang; Bian, Guang; Strocov, Vladimir N; Chang, Guoqing; Neupane, Madhab; Alidoust, Nasser; Sanchez, Daniel; Zheng, Hao; Brahlek, Matthew; Rogalev, Victor; Kim, Timur; Plumb, Nicholas C; Chen, Chaoyu; Bertran, François; Le Fèvre, Patrick; Taleb-Ibrahimi, Amina; Asensio, Maria-Carmen; Shi, Ming; Lin, Hsin; Hoesch, Moritz; Oh, Seongshik; Hasan, M Zahid
2017-03-01
Engineered lattices in condensed matter physics, such as cold-atom optical lattices or photonic crystals, can have properties that are fundamentally different from those of naturally occurring electronic crystals. We report a novel type of artificial quantum matter lattice. Our lattice is a multilayer heterostructure built from alternating thin films of topological and trivial insulators. Each interface within the heterostructure hosts a set of topologically protected interface states, and by making the layers sufficiently thin, we demonstrate for the first time a hybridization of interface states across layers. In this way, our heterostructure forms an emergent atomic chain, where the interfaces act as lattice sites and the interface states act as atomic orbitals, as seen from our measurements by angle-resolved photoemission spectroscopy. By changing the composition of the heterostructure, we can directly control hopping between lattice sites. We realize a topological and a trivial phase in our superlattice band structure. We argue that the superlattice may be characterized in a significant way by a one-dimensional topological invariant, closely related to the invariant of the Su-Schrieffer-Heeger model. Our topological insulator heterostructure demonstrates a novel experimental platform where we can engineer band structures by directly controlling how electrons hop between lattice sites.
Observation of a Dissipative Phase Transition in a One-Dimensional Circuit QED Lattice
Directory of Open Access Journals (Sweden)
Mattias Fitzpatrick
2017-02-01
Full Text Available Condensed matter physics has been driven forward by significant experimental and theoretical progress in the study and understanding of equilibrium phase transitions based on symmetry and topology. However, nonequilibrium phase transitions have remained a challenge, in part due to their complexity in theoretical descriptions and the additional experimental difficulties in systematically controlling systems out of equilibrium. Here, we study a one-dimensional chain of 72 microwave cavities, each coupled to a superconducting qubit, and coherently drive the system into a nonequilibrium steady state. We find experimental evidence for a dissipative phase transition in the system in which the steady state changes dramatically as the mean photon number is increased. Near the boundary between the two observed phases, the system demonstrates bistability, with characteristic switching times as long as 60 ms—far longer than any of the intrinsic rates known for the system. This experiment demonstrates the power of circuit QED systems for studying nonequilibrium condensed matter physics and paves the way for future experiments exploring nonequilbrium physics with many-body quantum optics.
Exciton size and binding energy limitations in one-dimensional organic materials
Energy Technology Data Exchange (ETDEWEB)
Kraner, S., E-mail: stefan.kraner@iapp.de; Koerner, C.; Leo, K. [Institut für Angewandte Photophysik, Technische Universität Dresden, Dresden (Germany); Scholz, R. [Institut für Angewandte Photophysik, Technische Universität Dresden, Dresden (Germany); Dresden Center of Computational Materials Science, Technische Universität Dresden, D-01062 Dresden (Germany); Plasser, F. [Institute for Theoretical Chemistry, University of Vienna, A-1090 Vienna (Austria)
2015-12-28
In current organic photovoltaic devices, the loss in energy caused by the charge transfer step necessary for exciton dissociation leads to a low open circuit voltage, being one of the main reasons for rather low power conversion efficiencies. A possible approach to avoid these losses is to tune the exciton binding energy to a value of the order of thermal energy, which would lead to free charges upon absorption of a photon, and therefore increase the power conversion efficiency towards the Shockley-Queisser limit. We determine the size of the excitons for different organic molecules and polymers by time dependent density functional theory calculations. For optically relevant transitions, the exciton size saturates around 0.7 nm for one-dimensional molecules with a size longer than about 4 nm. For the ladder-type polymer poly(benzimidazobenzophenanthroline), we obtain an exciton binding energy of about 0.3 eV, serving as a lower limit of the exciton binding energy for the organic materials investigated. Furthermore, we show that charge transfer transitions increase the exciton size and thus identify possible routes towards a further decrease of the exciton binding energy.
Localized modes in orientation-disordered one-dimensional media with uniaxial scatterers
Institute of Scientific and Technical Information of China (English)
Yingmao Xie; Zhengdong Liu
2008-01-01
Localized modes in one-dimensional (1D) media with uniaxial scatterers that are assumed to be order in spatial location but disorder in spatial orientation of their optical axis are investigated. Based on the holistic effect model in random laser, I.e., the random laser is due to the interaction of the complex localized modes in active random media with local aperiodic quasi-structure with appropriate pump light, a physical model on this type of random media is found. Its disorder degree is defined by D = no/ne. Then, the typical transmission spectrum through the random media and the light field intensity distribution corresponding to the defect modes in photonic band-gap are calculated numerically by means of the transfer matrix method, and the condition that the localized mode appears is discussed. Results show that the medium disorder plays an important role in determining the lightwave state. The localized state appears when the medium disorder is strong enough, and a new mechanism creating random laser phenomenon is brought forward.
One-dimensional Array Grammars and P Systems with Array Insertion and Deletion Rules
Directory of Open Access Journals (Sweden)
Rudolf Freund
2013-09-01
Full Text Available We consider the (one-dimensional array counterpart of contextual as well as insertion and deletion string grammars and consider the operations of array insertion and deletion in array grammars. First we show that the emptiness problem for P systems with (one-dimensional insertion rules is undecidable. Then we show computational completeness of P systems using (one-dimensional array insertion and deletion rules even of norm one only. The main result of the paper exhibits computational completeness of one-dimensional array grammars using array insertion and deletion rules of norm at most two.
Stationary bottom generated velocity fluctuations in one-dimensional open channel flow
Jong, de Bartele
1993-01-01
Statistical characteristics are calculated for stationary velocity fluctuations in a one-dimensional open channel flow with a given vertical velocity profile and with one-dimensional irregular bottom waves, characterized by a spectral density function. The calculations are based on an approximate ca
Synthesis and magneticproperties of one-dimensional Mn(Ⅱ) complexes linked bydithiooxalato
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
Three dithiooxalato (Dto) bridging one-dimensional Mn(Ⅱ) complexes [Mn(L)Dto](L = Phen (1), Bpy (2) and en (3)) were synthesized. All of the complexes have the similar one-dimensional structure through Dto bridge. The measurement of the variable temperature magnetic susceptibility of complex 1 showed that there are weak antiferromag- netic interactions between the Mn(Ⅱ) ions.
Li, Lei; Liang, Lizhi; Wu, Heng; Zhu, Xinhua
2016-12-01
One-dimensional nanostructures, including nanowires, nanorods, nanotubes, nanofibers, and nanobelts, have promising applications in mesoscopic physics and nanoscale devices. In contrast to other nanostructures, one-dimensional nanostructures can provide unique advantages in investigating the size and dimensionality dependence of the materials' physical properties, such as electrical, thermal, and mechanical performances, and in constructing nanoscale electronic and optoelectronic devices. Among the one-dimensional nanostructures, one-dimensional perovskite manganite nanostructures have been received much attention due to their unusual electron transport and magnetic properties, which are indispensable for the applications in microelectronic, magnetic, and spintronic devices. In the past two decades, much effort has been made to synthesize and characterize one-dimensional perovskite manganite nanostructures in the forms of nanorods, nanowires, nanotubes, and nanobelts. Various physical and chemical deposition techniques and growth mechanisms are explored and developed to control the morphology, identical shape, uniform size, crystalline structure, defects, and homogenous stoichiometry of the one-dimensional perovskite manganite nanostructures. This article provides a comprehensive review of the state-of-the-art research activities that focus on the rational synthesis, structural characterization, fundamental properties, and unique applications of one-dimensional perovskite manganite nanostructures in nanotechnology. It begins with the rational synthesis of one-dimensional perovskite manganite nanostructures and then summarizes their structural characterizations. Fundamental physical properties of one-dimensional perovskite manganite nanostructures are also highlighted, and a range of unique applications in information storages, field-effect transistors, and spintronic devices are discussed. Finally, we conclude this review with some perspectives/outlook and future
Effect of interchain frustration in quasi-one-dimensional conductors at half-filling
Tsuchiizu, M.; Suzumura, Y.; Bourbonnais, C.
2007-04-01
We examine the effect of frustrated interchain hoppings t_{\\perp 1} and t_{\\perp 2} on one-dimensional Mott insulators. By applying an N_\\perp -chain two-loop renormalization-group method to the half-filled quasi-one-dimensional Hubbard model, we show that the system remains insulating even for the large t_{\\perp 1} as far as t_{\\perp 2}=0 and vice versa, whereas a metallic state emerges by increasing both interchain hoppings. We also discuss the metallic behaviour suggested in the quasi-one-dimensional organic compound (TTM-TTP)I3 under high pressure.
A Large Class of Exact Solutions to the One-Dimensional Schrodinger Equation
Karaoglu, Bekir
2007-01-01
A remarkable property of a large class of functions is exploited to generate exact solutions to the one-dimensional Schrodinger equation. The method is simple and easy to implement. (Contains 1 table and 1 figure.)
Steen-Ermakov-Pinney equation and integrable nonlinear deformation of one-dimensional Dirac equation
Prykarpatskyy, Yarema
2017-01-01
The paper deals with nonlinear one-dimensional Dirac equation. We describe its invariants set by means of the deformed linear Dirac equation, using the fact that two ordinary differential equations are equivalent if their sets of invariants coincide.
ABOUT OF SOME ONE-DIMENSIONAL OPTIMIZATION ALGORITHMS WITH ECONOMIC APPLICATIONS
Directory of Open Access Journals (Sweden)
Radu R. Şerban
2012-12-01
Full Text Available In this paper, a new algorithm for one dimensional optimization is presented. The algorithm is based on the “parabola tangent” method for solving a class of equations, without divergence points.
Computational method for the quantum Hamilton-Jacobi equation: one-dimensional scattering problems.
Chou, Chia-Chun; Wyatt, Robert E
2006-12-01
One-dimensional scattering problems are investigated in the framework of the quantum Hamilton-Jacobi formalism. First, the pole structure of the quantum momentum function for scattering wave functions is analyzed. The significant differences of the pole structure of this function between scattering wave functions and bound state wave functions are pointed out. An accurate computational method for the quantum Hamilton-Jacobi equation for general one-dimensional scattering problems is presented to obtain the scattering wave function and the reflection and transmission coefficients. The computational approach is demonstrated by analysis of scattering from a one-dimensional potential barrier. We not only present an alternative approach to the numerical solution of the wave function and the reflection and transmission coefficients but also provide a computational aspect within the quantum Hamilton-Jacobi formalism. The method proposed here should be useful for general one-dimensional scattering problems.
Theory of optimal beam splitting by phase gratings. I. One-dimensional gratings.
Romero, Louis A; Dickey, Fred M
2007-08-01
We give an analytical basis for the theory of optimal beam splitting by one-dimensional gratings. In particular, we use methods from the calculus of variations to derive analytical expressions for the optimal phase function.
Institute of Scientific and Technical Information of China (English)
LIU Shi-Kuo; GAO Bin; FU Zun-Tao; LIU Shi-Da
2009-01-01
In this paper, applying the dependent and independent variables transformations as well as the Jacobi elliptic function expansion method, the envelope periodic solutions to one-dimensional Gross-Pitaevskii equation in Bose-Einstein condensates are obtained.
Exact solution to the one-dimensional Dirac equation of linear potential
Institute of Scientific and Technical Information of China (English)
Long Chao-Yun; Qin Shui-Jie
2007-01-01
In this paper the one-dimensional Dirac equation with linear potential has been solved by the method of canonical transformation. The bound-state wavefunctions and the corresponding energy spectrum have been obtained for all bound states.
Modeling of an one-dimensional harmonious ostsillyator in the environment of MATLAB/SIMULINK
Directory of Open Access Journals (Sweden)
B. A. Golodenko
2012-01-01
Full Text Available Results of modeling one-dimensional harmonious oscillator are stated by means MATLAB/SIMULINK. On example oscillators, possible approaches and technologies of construction of models of real physical systems based on their mathematical description are shown.
Goloviznin, V. M.; Kanaev, A. A.
2012-03-01
The CABARET computational algorithm is generalized to one-dimensional scalar quasilinear hyperbolic partial differential equations with allowance for inequality constraints on the solution. This generalization can be used to analyze seepage of liquid radioactive wastes through the unsaturated zone.
Prediction of inorganic superconductors with quasi-one-dimensional crystal structure
Volkova, L. M.; Marinin, D. V.
2012-01-01
Models of superconductors having a quasi-one-dimensional crystal structure based on the convoluted into a tube Ginzburg sandwich, which comprises a layered dielectric-metal-dielectric structure, have been suggested. The critical crystal chemistry parameters of the Ginzburg sandwich determining the possibility of the emergence of superconductivity and the Tc value in layered high-Tc cuprates, which could have the same functions in quasi-one-dimensional fragments (sandwich-type tubes), have bee...
Note on Invariance of One-Dimensional Lattice-Boltzmann Equation
Institute of Scientific and Technical Information of China (English)
RAN Zheng
2007-01-01
Invariance of the one-dimensional lattice Boltzmann model is proposed together with its rigorous theoretical background.It is demonstrated that the symmetry inherent in Navier-Stokes equations is not really recovered in the one-dimensional lattice Boltzmann equation (LBE),especially for shock calculation.Symmetry breaking may be the inherent cause for the non-physical oscillations in the vicinity of the shock for LBE calculation.
An approach to one-dimensional elliptic quasi-exactly solvable models
Indian Academy of Sciences (India)
M A Fasihi; M A Jafarizadeh; M Rezaei
2008-04-01
One-dimensional Jacobian elliptic quasi-exactly solvable second-order differential equations are obtained by introducing the generalized third master functions. It is shown that the solutions of these differential equations are generating functions for a new set of polynomials in terms of energy with factorization property. The roots of these polynomials are the same as the eigenvalues of the differential equations. Some one-dimensional elliptic quasi-exactly quantum solvable models are obtained from these differential equations.
One- and Two- Magnon Excitations in a One-Dimensional Antiferromagnet in a Magnetic Field
DEFF Research Database (Denmark)
Heilmann, I.U.; Kjems, Jørgen; Endoh, Y.;
1981-01-01
We have carried out a comprehensive experimental and theoretical study of the inelastic scattering in the one-dimensional near-Heisenberg antiferromagnet (CD3)4NMnCl3 (TMMC) at low temperatures, 0.3......We have carried out a comprehensive experimental and theoretical study of the inelastic scattering in the one-dimensional near-Heisenberg antiferromagnet (CD3)4NMnCl3 (TMMC) at low temperatures, 0.3...
Effective one-dimensionality of universal ac hopping conduction in the extreme disorder limit
DEFF Research Database (Denmark)
Dyre, Jeppe; Schrøder, Thomas
1996-01-01
A phenomenological picture of ac hopping in the symmetric hopping model (regular lattice, equal site energies, random energy barriers) is proposed according to which conduction in the extreme disorder limit is dominated by essentially one-dimensional "percolation paths." Modeling a percolation path...... as strictly one dimensional with a sharp jump rate cutoff leads to an expression for the universal ac conductivity that fits computer simulations in two and three dimensions better than the effective medium approximation....
The effect of cross flow on one-dimensional spectra measured using hot wires
Ewing, D.
Expressions were developed to estimate the cross-flow error that occurs in the one-dimensional velocity spectra determined by applying Taylor's frozen field hypothesis to measurements with single- and cross-wire probes. The cross-flow error and the error caused by the unsteady convection of the small-scale motions were evaluated for typical measurements. It was found that the cross-flow error could be significant in inertial range of the measured one-dimensional spectra, and was much larger than the error caused by the unsteady convection of the small-scale motions in the one-dimensional spectra of the cross-stream velocity components, $ F2}{22 {( {k1 } )} and F1}{33 {( {k1 } )} . The results indicate that the one-dimensional spectra of the streamwise velocity component F1}{11 {( {k1 } )} $ measured with a single-wire probe should be significantly more accurate than the spectra measured with a cross-wire probe. The cross-flow error in the one-dimensional spectra also becomes much less important in the dissipation range of the measured spectra.
Wu, Xiang-Yao; Yang, Jing-Hai; Liu, Xiao-Jing; Ba, Nuo; Wu, Yi-Heng; Wang, Qing-Cai; Li, Jing-Wu
2010-01-01
In the paper, we present a new kind of function photonic crystals, which refractive index is a function of space position. Unlike conventional PCs, which structure grow from two materials, A and B, with different dielectric constants $\\epsilon_{A}$ and $\\epsilon_{B}$. By Fermat principle, we give the motion equations of light in one-dimensional, two-dimensional and three-dimensional function photonic crystals. For one-dimensional function photonic crystals, we study the dispersion relation, band gap structure and transmissivity, and compare them with conventional photonic crystals. By choosing various refractive index distribution function $n(z)$, we can obtain more width or more narrow band gap structure than conventional photonic crystals.
Institute of Scientific and Technical Information of China (English)
LI De-Jun; MI Xian-Wu; DENG Ke; TANG Yi
2006-01-01
In the classical lattice theory, solitons and locaLized modes can exist in many one-dimensional nonlinear lattice chains, however, in the quantum lattice theory, whether quantum solitons and localized modes can exist or not in the one-dimensional lattice chains is an interesting problem. By using the number state method and the Hartree approximation combined with the method of multiple scales, we investigate quantum solitons and localized modes in a one-dimensional lattice chain with the nonlinear substrate potential. It is shown that quantum solitons do exist in this nonlinear lattice chain, and at the boundary of the phonon Brillouin zone, quantum solitons become quantum localized modes, phonons are pinned to the lattice of the vicinity at the central position j = j0.
Multi-site Compact-Like Discrete Breather in Discrete One-Dimensional Monatomic Chains
Institute of Scientific and Technical Information of China (English)
XU Quan; TIAN Qiang
2007-01-01
Multi-site compact-like discrete breathers in djscrete one-dimensional monatomic chains are irIvestigated by discussing a generalized discrete one-dimensional monatomic model.We obtain that the two-site compact-like discrete breathers with codes σ={0,…,0,1,1,0…,0}and codes σ={0,…,0,1,-1,0…,0}can exist in discrete one-dimensional monatomic chain with quartic on-site and inter-site potentials.However,the former can only exist in hard quartic on-site potential and cannot exist in soft quartic on-site potential,whereas the latter is just reversed.All of the two-site Compact-like discrete breathers with codes σ={0,…,0,1,1,0,…,0}and σ={0,…,0,1,-1,0…,0}cannot exist in a pure K4 chain.
Directory of Open Access Journals (Sweden)
Saleh Alsubari
2011-09-01
Full Text Available In this paper, we present the mechanical models that are devoted to the elastic properties of one-dimensional composite. We have compared the equivalent coefficients of one-dimensional composite, resulting from different models. The validation of the results was made through effective experiments on a one-dimensional composite consisting of fibers of alumina and a matrix of aluminum. This study allows us to better assess the rigidity of composite structures, and the results of calculation of the mechanical behavior, resulting from each model. It appears that the finite element model is the best suited to the approach of a refined conception. For more insurance, we have chosen to make our calculations by finite element in the three-dimensional case, using the technique of homogenization by asymptotic development.
Hydrothermal Synthesis and Characterization of Nd Doped One-dimensional Hexagonal CePO_4 Nanowires
Institute of Scientific and Technical Information of China (English)
张新奇
2012-01-01
One-dimensional Nd doped CePO4 hexagonal nanowires have been synthesized for the first time at 140 ℃ for 24 hours via a hydrothermal method using P123 surfactant as the template.The products were characterized by X-ray diffraction,transmission electron microscopy,photoluminescence and high-resolution transmission electron microscopy.Compared with CePO4,one-dimensional nanomaterials we have synthesized,Nd doped CePO4 nanomaterials remain their hexagonal one-dimensional morphology and smooth surface.However,their photoluminescence emissions are greatly enhanced at the wavelength of 348 nm.With their novel fluorescence-emission property,the Nd doped CePO4 nanomaterials are potential in many fields such as optics and electronics.
Robust unidirectional transport in a one-dimensional metacrystal with long-range hopping
Longhi, Stefano
2016-01-01
In two- and three-dimensional structures, topologically-protected chiral edge modes offer a powerful mean to realize robust light transport. However, little attention has been paid so far to robust one-way transport in one-dimensional systems. Here it is shown that unidirectional transport, which is immune to disorder and backscattering, can occur in certain one-dimensional metacrystals with long-range hopping without resorting to topological protection. Such metacrystals are described by an effective Hermitian Hamiltonian with broken time reversal symmetry, and transport does not require adiabatic (Thouless) pumping. A simple implementation in optics of such one-dimensional metacrystals, based on transverse light dynamics in a self-imaging optical cavity with phase gratings, is suggested
Visualizing One-Dimensional Electronic States and their Scattering in Semi-conducting Nanowires
Beidenkopf, Haim; Reiner, Jonathan; Norris, Andrew; Nayak, Abhay Kumar; Avraham, Nurit; Shtrikman, Hadas
One-dimensional electronic systems constitute a fascinating playground for the emergence of exotic electronic effects and phases, within and beyond the Tomonaga-Luttinger liquid paradigm. More recently topological superconductivity and Majorana modes were added to that long list of phenomena. We report scanning tunneling microscopy and spectroscopy measurements conducted on pristine, epitaxialy grown InAs nanowires. We resolve the 1D electronic band structure manifested both via Van-Hove singularities in the local density-of-states, as well as by the quasi-particle interference patterns, induced by scattering from surface impurities. By studying the scattering of the one-dimensional electronic states off various scatterers, including crystallographic defects and the nanowire end, we identify new one-dimensional relaxation regimes and yet unexplored effects of interactions. Some of these may bear implications on the topological superconducting state and Majorana modes therein. The authors acknowledge support from the Israeli Science Foundation (ISF).
Kemp, K J; Guthrie, J; Hagood, B; Havey, M D
2016-01-01
The phenomenon of electronic wave localization through disorder was introduced by Anderson in 1958 in the context of electron transport in solids. It remains an important area of fundamental and applied research. Localization of all wave phenomena, including light, is thought to exist in a restricted one dimensional geometry. We present here a series of experiments which illustrate, using a simple experimental arrangement and approach, localization of light in a quasi one dimensional physical system. In the experiments, reflected and transmitted light from a stack of glass slides of varying thickness reveals an Ohm's Law type behavior for small thicknesses, and evolution to exponential decay of the transmitted power for thicker slide stacks. Light absorption is negligible in our realization of the experiment. For larger stacks of slides, weak departure from a one dimensional behavior is also observed. The experiment and analysis of the results, then showing many of the essential features of wave localization,...
Kemp, K. J.; Barker, S.; Guthrie, J.; Hagood, B.; Havey, M. D.
2016-10-01
The phenomenon of electronic wave localization through disorder remains an important area of fundamental and applied research. Localization of all wave phenomena, including light, is thought to exist in a restricted one-dimensional geometry. We present here a series of experiments to illustrate, using a straightforward experimental arrangement and approach, the localization of light in a quasi-one-dimensional physical system. In the experiments, reflected and transmitted light from a stack of glass slides of varying thickness reveals an Ohm's law type behavior for small thicknesses, and evolution to exponential decay of the transmitted power for larger thicknesses. For larger stacks of slides, a weak departure from one-dimensional behavior is also observed. The experiment and analysis of the results, showing many of the essential features of wave localization, is relatively straightforward, economical, and suitable for laboratory experiments at an undergraduate level.
Pearsall, Thomas P
2017-01-01
This textbook employs a pedagogical approach that facilitates access to the fundamentals of Quantum Photonics. It contains an introductory description of the quantum properties of photons through the second quantization of the electromagnetic field, introducing stimulated and spontaneous emission of photons at the quantum level. Schrödinger’s equation is used to describe the behavior of electrons in a one-dimensional potential. Tunneling through a barrier is used to introduce the concept of nonlocality of an electron at the quantum level, which is closely-related to quantum confinement tunneling, resonant tunneling, and the origin of energy bands in both periodic (crystalline) and aperiodic (non-crystalline) materials. Introducing the concepts of reciprocal space, Brillouin zones, and Bloch’s theorem, the determination of electronic band structure using the pseudopotential method is presented, allowing direct computation of the band structures of most group IV, group III-V, and group II-VI semiconducto...
Institute of Scientific and Technical Information of China (English)
YANG XiaoXue; WU Ying
2002-01-01
We develop a simple approach to obtain explicitly exact analytical expressions of particle and kinetic-energy densities for noninteracting Fermi gases in one-dimensional harmonic confinement, and in one-dimensional boxconfinement as well.
One dimensional Si/Sn - based nanowires and nanotubes for lithium-ion energy storage materials
Choi, Nam-Soon
2011-01-01
There has been tremendous interest in using nanomaterials for advanced Li-ion battery electrodes, particularly to increase the energy density by using high specific capacity materials. Recently, it was demonstrated that one dimensional (1D) Si/Sn nanowires (NWs) and nanotubes (NTs) have great potential to achieve high energy density as well as long cycle life for the next generation of advanced energy storage applications. In this feature article, we review recent progress on Si-based NWs and NTs as high capacity anode materials. Fundamental understanding and future challenges on one dimensional nanostructured anode are also discussed. © 2010 The Royal Society of Chemistry.
UNIVERSAL THEORY OF STEADY-STATE ONE-DIMENSIONAL PHOTOREFRACTIVE SOLITONS
Institute of Scientific and Technical Information of China (English)
刘劲松
2001-01-01
A universal theory of steady-state one-dimensional photorefractive spatial solitons is developed which applies to the steady-state one-dimensional photorefractive solitons under various realizations, including the screening solitons in a biased photorefractive medium, the photovoltaic solitons in open- and closed-circuit photovoltaic-photorefractive media and the screening-photovoltaic solitons in biased photovoltaic-photorefractive media. Previous theories advanced individually elsewhere for these solitons can be obtained by simplifying the universal theory under the appropriate conditions.
Generalization of the one-dimensional ideal plasma flow with spherical waves
Energy Technology Data Exchange (ETDEWEB)
Golovin, Sergey V [Queen' s University, Kingston, Ontario K7 L 3N6 (Canada)
2006-06-09
We give a description of the ideal plasma flow, which is governed by an exact partially invariant solution of the magnetohydrodynamics equations. The solution generalizes known one-dimensional flow with spherical waves. The generalization consists in addition of the special tangent vector components of the velocity and the magnetic field at any plasma particle. In the special case of zeroth tangential component the solution coincides with the classical one-dimensional one. This paper describes a three-dimensional picture of the plasma flow, governed by the obtained solution.
Metal-insulator transition in one-dimensional lattices with chaotic energy sequences
Energy Technology Data Exchange (ETDEWEB)
Pinto, R.A. [Laboratorio de Fisica Estadistica, Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A (Venezuela)]. E-mail: ripinto@ivic.ve; Rodriguez, M. [Laboratorio de Fisica Estadistica, Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A (Venezuela); Gonzalez, J.A. [Laboratorio de Fisica Computacional, Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A (Venezuela); Medina, E. [Laboratorio de Fisica Estadistica, Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A (Venezuela)
2005-06-20
We study electronic transport through a one-dimensional array of sites by using a tight binding Hamiltonian, whose site-energies are drawn from a chaotic sequence. The correlation degree between these energies is controlled by a parameter regulating the dynamic Lyapunov exponent measuring the degree of chaos. We observe the effect of chaotic sequences on the localization length, conductance, conductance distribution and wave function, finding evidence of a metal-insulator transition (MIT) at a critical degree of chaos. The one-dimensional metallic phase is characterized by a Gaussian conductance distribution and exhibits a peculiar non-selfaveraging.
Neutron beam applications - Development of one dimensional position sensitive neutron detector
Energy Technology Data Exchange (ETDEWEB)
Lee, Sang Yun; Kang, Hee Dong; Kim, Wan; Moon, Myung Kook [Kyungpook National University, Taegu (Korea)
2000-04-01
This research is sponsored and supported by KAERI as a part of {sup D}evelopment of One Dimensional Position Sensitive Neutron Detector{sup .} To apply residual stress measurement and small angle neutron scattering the one dimensional position sensitive neutron detectors which have wide window and good position resolution were designed and fabricated. The detection area are 200 mm x 100, 120 mm x 80 mm. The thermal neutron detection efficiency are about 60%. The spatial resolution of the detector are less than 2mm. The characteristics of the detectors were studied. Using the detector we could get neutron diffraction patterns from some samples. 19 refs., 103 figs., 4 tabs. (Author)
Fluctuations of the heat flux of a one-dimensional hard particle gas
Brunet, E.; Derrida, B.; Gerschenfeld, A.
2010-04-01
Momentum-conserving one-dimensional models are known to exhibit anomalous Fourier's law, with a thermal conductivity varying as a power law of the system size. Here we measure, by numerical simulations, several cumulants of the heat flux of a one-dimensional hard particle gas. We find that the cumulants, like the conductivity, vary as power laws of the system size. Our results also indicate that cumulants higher than the second follow different power laws when one compares the ring geometry at equilibrium and the linear case in contact with two heat baths (at equal or unequal temperatures).
Institute of Scientific and Technical Information of China (English)
刘保国; 殷学纲; 蹇开林; 吴永
2003-01-01
A general method based on Riccati transfer matrix is presented to calculate the2 nd order perturbations of eigendatas for one-dimensional structural system with parameteruncertainties. The method is applicable to both real and complex eigendatas of any one-dimensional structural system. The formulas for calculating the sensitivity derivatives ofeigendatas based on this method are also presented. The method is applied to theperturbation analysis for the eigendatas of a rotor with gyroscopic moment, and thedifferences between the perturbation results and the accurate calculating results are small.
Extended Wronskian Determinant Approach and Iterative Solutions of One-Dimensional Dirac Equation
Institute of Scientific and Technical Information of China (English)
XU Ying; LU Meng; SU Ru-Keng
2004-01-01
An approximation method, namely, the Extended Wronskian Determinant Approach, is suggested to study the one-dimensional Dirac equation. An integral equation, which can be solved by iterative procedure to find the wave functions, is established. We employ this approach to study the one-dimensional Dirac equation with one-well potential,and give the energy levels and wave functions up to the first order iterative approximation. For double-well potential,the energy levels up to the first order approximation are given.
Von Neumann Entropy of an Electron in One-Dimensional Determined Potentials
Institute of Scientific and Technical Information of China (English)
GONG Long-Yan; TONG Pei-Qing
2005-01-01
@@ By using the measure of von Neumann entropy, we numerically investigate quantum entanglement of an electronmoving in the one-dimensional Harper model and in the one-dimensional slowly varying potential model. Thedelocalized and localized eigenstates can be distinguished by von Neumann entropy of the individual eigenstates.There are drastic decreases in yon Neumann entropy of the individual eigenstates at mobility edges. In the curveof the spectrum averaged yon Neumann entropy as a function of potential parameter λ, a sharp transition existsat the metal-insulator transition point λc = 2. It is found that the yon Neumann entropy is a good quantity toreflect localization and metal-insulator transition.
Quantum quenches to the attractive one-dimensional Bose gas: exact results
Directory of Open Access Journals (Sweden)
Lorenzo Piroli, Pasquale Calabrese, Fabian H. L. Essler
2016-09-01
Full Text Available We study quantum quenches to the one-dimensional Bose gas with attractive interactions in the case when the initial state is an ideal one-dimensional Bose condensate. We focus on properties of the stationary state reached at late times after the quench. This displays a finite density of multi-particle bound states, whose rapidity distribution is determined exactly by means of the quench action method. We discuss the relevance of the multi-particle bound states for the physical properties of the system, computing in particular the stationary value of the local pair correlation function $g_2$.
Exact and LDA entanglement of tailored densities in an interacting one-dimensional electron system
Energy Technology Data Exchange (ETDEWEB)
Coe, J P; D' Amico, I, E-mail: jpc503@york.ac.u, E-mail: ida500@york.ac.u [Department of Physics, University of York, York YO10 5DD (United Kingdom)
2010-01-01
We calculate the 'exact' potential corresponding to a one-dimensional interacting system of two electrons with a specific, tailored density. We use one-dimensional density-functional theory with a local-density approximation (LDA) on the same system and calculate densities and energies, which are compared with the 'exact' ones. The 'interacting-LDA system'[4] corresponding to the LDA density is then found and its potential compared with the original one. Finally we calculate and compare the spatial entanglement of the electronic systems corresponding to the interacting-LDA and original interacting system.
Lagrangian formulation of the one-dimensional Vlasov equation. [in plasma physics
Lewak, G. J.
1974-01-01
A new formulation of the one-dimensional Vlasov equation is derived which is analogous to the Kalman-transformed cold-plasma equations. The equations are shown to yield nonsecular, nonlinear approximations to a source or boundary-value problem. It is suggested that the formulation may have other applications in nonlinear plasma theory.
Electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ
DEFF Research Database (Denmark)
Sing, M.; Schwingenschlögl, U.; Claessen, R.;
2003-01-01
We study the electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ by means of density-functional band theory, Hubbard model calculations, and angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant quantitative and qualitative...
One-dimensional organic lead halide perovskites with efficient bluish white-light emission
Yuan, Zhao; Zhou, Chenkun; Tian, Yu; Shu, Yu; Messier, Joshua; Wang, Jamie C.; van de Burgt, Lambertus J.; Kountouriotis, Konstantinos; Xin, Yan; Holt, Ethan; Schanze, Kirk; Clark, Ronald; Siegrist, Theo; Ma, Biwu
2017-01-01
Organic-inorganic hybrid metal halide perovskites, an emerging class of solution processable photoactive materials, welcome a new member with a one-dimensional structure. Herein we report the synthesis, crystal structure and photophysical properties of one-dimensional organic lead bromide perovskites, C4N2H14PbBr4, in which the edge sharing octahedral lead bromide chains [PbBr4 2-]∞ are surrounded by the organic cations C4N2H14 2+ to form the bulk assembly of core-shell quantum wires. This unique one-dimensional structure enables strong quantum confinement with the formation of self-trapped excited states that give efficient bluish white-light emissions with photoluminescence quantum efficiencies of approximately 20% for the bulk single crystals and 12% for the microscale crystals. This work verifies once again that one-dimensional systems are favourable for exciton self-trapping to produce highly efficient below-gap broadband luminescence, and opens up a new route towards superior light emitters based on bulk quantum materials.
Critical exponents in the transition to chaos in one-dimensional discrete systems
Indian Academy of Sciences (India)
G Ambika; N V Sujatha
2002-07-01
We report the numerically evaluated critical exponents associated with the scaling of generalized fractal dimensions during the transition from order to chaos. The analysis is carried out in detail in the context of unimodal and bimodal maps representing typical one-dimensional discrete dynamical systems. The behavior of Lyapunov exponents (LE) in the cross over region is also studied for a complete characterization.
Functional equation for the crossover in the model of one-dimensional Weierstrass random walks
Rudoi, Yu. G.; Kotel'nikova, O. A.
2016-12-01
We consider the problem of one-dimensional symmetric diffusion in the framework of Markov random walks of the Weierstrass type using two-parameter scaling for the transition probability. We construct a solution for the characteristic Lyapunov function as a sum of regular (homogeneous) and singular (nonhomogeneous) solutions and find the conditions for the crossover from normal to anomalous diffusion.
Observation of Zero-Dimensional States in a One-Dimensional Electron Interferometer
Wees, B.J. van; Kouwenhoven, L.P.; Harmans, C.J.P.M.; Williamson, J.G.; Timmering, C.E.; Broekaart, M.E.I.; Foxon, C.T.; Harris, J.J.
1989-01-01
We have studied the electron transport in a one-dimensional electron interferometer. It consists of a disk-shaped two-dimensional electron gas, to which quantum point contacts are attached. Discrete zero-dimensional states are formed due to constructive interference of electron waves traveling along
DEFF Research Database (Denmark)
Johannessen, Kim
2014-01-01
The exact solution to the one-dimensional Poisson–Boltzmann equation with asymmetric boundary conditions can be expressed in terms of the Jacobi elliptic functions. The boundary conditions determine the modulus of the Jacobi elliptic functions. The boundary conditions can not be solved analytically...
Absolute and convective instabilities in a one-dimensional Brusselator flow model
DEFF Research Database (Denmark)
Kuznetsov, S.P.; Mosekilde, Erik; Dewel, G.
1997-01-01
The paper considers a one-dimensional Brusselator model with a uniform flow of the mixture of reaction components. An absolute as well as a convective instability can arise for both the Hopf and the Turing modes. The corresponding linear stability analysis is presented and supported by the results...
Apparent power-law behavior of conductance in disordered quasi-one-dimensional systems.
Rodin, A S; Fogler, M M
2010-09-03
The dependence of hopping conductance on temperature and voltage for an ensemble of modestly long one-dimensional wires is studied numerically using the shortest-path algorithm. In a wide range of parameters this dependence can be approximated by a power law rather than the usual stretched-exponential form. The relation to recent experiments and prior analytical theory is discussed.
Explicit solutions of one-dimensional, first-order, stationary mean-field games with congestion
Gomes, Diogo A.
2017-01-05
Here, we consider one-dimensional first-order stationary mean-field games with congestion. These games arise when crowds face difficulty moving in high-density regions. We look at both monotone decreasing and increasing interactions and construct explicit solutions using the current formulation. We observe new phenomena such as discontinuities, unhappiness traps and the non-existence of solutions.
Controllable plasma energy bands in a one-dimensional crystal of fractional Josephson vortices
Susanto, H.; Goldobin, E.; Koelle, D.; Kleiner, R.; Gils, van S.A.
2005-01-01
We consider a one-dimensional chain of fractional vortices in a long Josephson junction with alternating ±kappa phase discontinuities. Since each vortex has its own eigenfrequency, the intervortex coupling results in eigenmode splitting and in the formation of an oscillatory energy band for plasma w
Vortex-lattice melting in a one-dimensional optical lattice
Snoek, M.; Stoof, H.T.C.
2006-01-01
We investigate quantum fluctuations of a vortex lattice in a one-dimensional optical lattice. Our method gives full access to all the modes of the vortex lattice and we discuss in particular the Bloch bands of the Tkachenko modes. Because of the small number of particles in the pancake
Theory of vortex-lattice melting in a one-dimensional optical lattice
Snoek, M.; Stoof, H.T.C.
2006-01-01
We investigate quantum and temperature fluctuations of a vortex lattice in a one-dimensional optical lattice. We discuss in particular the Bloch bands of the Tkachenko modes and calculate the correlation function of the vortex positions along the direction of the optical lattice. Because of the
Vortex-lattice melting in a one-dimensional optical lattice
Snoek, M.; Stoof, H.T.C.
2006-01-01
We investigate quantum fluctuations of a vortex lattice in a one-dimensional optical lattice for realistic numbers of particles and vortices. Our method gives full access to all the modes of the vortex lattice and we discuss in particular the Bloch bands of the Tkachenko modes. Because of the
Study on one-dimensional consolidation of soil under cyclic loading and with varied compressibility
Institute of Scientific and Technical Information of China (English)
ZHUANG Ying-chun; XIE Kang-he
2005-01-01
This paper presents a semi-analytical method to solve one dimensional consolidation problem by taking consideration of varied compressibility of soil under cyclic loading. In the method, soil stratum is divided equally into n layers while load and consolidation time are also divided into small parts and time intervals accordingly. The problem of one-dimensional consolidation of soil stratum under cyclic loading can then be dealt with at each time interval as one-dimensional linear consolidation of multi-layered soils under constant loading. The compression or rebounding of each soil layer can be judged by the effective stress of the layer. When the effective stress is larger than that in the last time interval, the soil layer is compressed, and when it is smaller, the soil layer rebounds. Thus, appropriate compressibility can be chosen and the consolidation of the layered system can be analyzed by the available analytical linear consolidation theory. Based on the semi-analytical method, a computer program was developed and the behavior of one-dimensional consolidation of soil with varied compressibility under cyclic loading was investigated, and compared with the available consolidation theory which takes no consideration of varied compressibility of soil under cyclic loading. The results showed that by taking the variable compressibility into account, the rate of consolidation of soil was greater than the one predicted by conventional consolidation theory.
Comparing the Impact of Dynamic and Static Media on Students' Learning of One-Dimensional Kinematics
Mešic, Vanes; Dervic, Dževdeta; Gazibegovic-Busuladžic, Azra; Salibašic, Džana; Erceg, Nataša
2015-01-01
In our study, we aimed to compare the impact of simulations, sequences of printed simulation frames and conventional static diagrams on the understanding of students with regard to the one-dimensional kinematics. Our student sample consisted of three classes of middle years students (N = 63; mostly 15 year-olds). These three classes served as…
Entanglement in One-Dimensional Random XY Spin Chain with Dzyaloshinskii-Moriya Interaction
Institute of Scientific and Technical Information of China (English)
SHAN Chuan-Jia; CHENG Wei-Wen; LIU Tang-Kun; HUANG Yan-Xia; LI Hong
2008-01-01
@@ The impurities of exchange couplings,external magnetic fields and Dzyaloshinskii-Moriya (DM)interaction considered as Ganssian distribution.and the entanglement in one-dimensional random XY spin systems is investigated by the method of solving the different spin-spin correlation functions and the average magnetization per spin.
Global solutions with infinite energy for the one-dimensional Zakharov system
Directory of Open Access Journals (Sweden)
Hartmut Pecher
2005-04-01
Full Text Available The one-dimensional Zakharov system is shown to have a unique global solution for data without finite energy. The proof uses the ``I-method'' introduced by Colliander, Keel, Staffilani, Takaoka, and Tao in connection with a refined bilinear Strichartz estimate.
Exact Solution to the One-Dimensional Dirac Equation with Time Varying Mass
Institute of Scientific and Technical Information of China (English)
YANG Jin; XIANG An-Ping; YU Wan-Lun
2003-01-01
We directly use the quantum-invariant operator method to obtain the closed-form solution to the one-dimensional Dirac equation with a time-changing mass with a little manipulation. The solution got is also applicable forthe case with time-independence mass.