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Optics

New submissions

[ total of 17 entries: 1-17 ]
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New submissions for Tue, 20 Mar 18

[1]  arXiv:1803.06419 [pdf, other]
Title: Topological Wave-Guiding Near an Exceptional Point: Defect-Immune, Slow-Light, Loss-Immune Propagation
Subjects: Optics (physics.optics)

Electromagnetic waves propagating, at finite speeds, in conventional wave-guiding structures are reflected by discontinuities and decay in lossy regions. In this Letter, we drastically modify this typical guided-wave behavior by combining concepts from non-Hermitian physics and topological photonics. To this aim, we theoretically study, for the first time, the possibility of realizing an exceptional point between \emph{coupled topological modes in a non-Hermitian non-reciprocal waveguide}. Our proposed system is composed of oppositely-biased gyrotropic materials (e.g., biased plasmas or graphene layers) with a balanced loss/gain distribution. To study this complex wave-guiding problem, we put forward an exact analysis based on classical Green's function theory, and we illustrate the behavior of coupled topological modes and the nature of their non-Hermitian degeneracies. We find that, by operating near an exceptional point, we can realize anomalous topological wave propagation with, at the same time, low group-velocity, inherent immunity to back-scattering at discontinuities, and immunity to losses. These theoretical findings may open exciting research directions and stimulate further investigations of non-Hermitian topological waveguides to realize robust wave propagation in practical scenarios.

[2]  arXiv:1803.06611 [pdf, ps, other]
Title: Active Manipulation of Electromagnetically Induced Transparency in a Terahertz Hybrid Metamaterial
Authors: Tingting Liu
Subjects: Optics (physics.optics)

The metamaterial analogue of electromagnetically induced transparency (EIT) in terahertz (THz) regime holds fascinating prospects for filling the THz gap in various functional devices. In this paper, we propose a novel hybrid metamaterial to actively manipulate the resonance strength of EIT effect. By integrating a monolayer graphene into a THz metal metamaterial, an on-to-off modulation of the EIT transparency window is achieved under different Fermi levels of graphene. According to the classical two-particle model and the distributions of the electric field and surface charge density, the physical mechanism is attributable to the recombination effect of conductive graphene. This work reveals a novel manipulation mechanism of EIT resonance in the hybrid metamaterial and offers a new perspective towards designing THz functional devices.

[3]  arXiv:1803.06616 [pdf]
Title: Actively controlling the topological transition of dispersion based on electrically controllable metamaterials
Comments: 21 pages,8 figures
Subjects: Optics (physics.optics)

Topological transition of the iso-frequency contour (IFC) from a closed ellipsoid to an open hyperboloid, will provide unique capabilities for controlling the propagation of light. However, the ability to actively tune these effects remains elusive and the related experimental observations are highly desirable. Here, tunable electric IFC in periodic structure which is composed of graphene/dielectric multilayers is investigated by tuning the chemical potential of graphene layer. Specially, we present the actively controlled transportation in two kinds of anisotropic zero-index media containing PEC/PMC impurities. At last, by adding variable capacitance diodes into two-dimensional transmission-line system, we present the experimental demonstration of the actively controlled magnetic topological transition of dispersion based on electrically controllable metamaterials. With the increase of voltage, we measure the different emission patterns from a point source inside the structure and observe the phase-transition process of IFCs. The realization of actively tuned topological transition will opens up a new avenue in the dynamical control of metamaterials.

[4]  arXiv:1803.06889 [pdf, other]
Title: Terahertz emission from laser-driven gas-plasmas: a plasmonic point of view
Subjects: Optics (physics.optics); Plasma Physics (physics.plasm-ph)

We investigate terahertz generation in two-color laser-induced gas plasmas. Resonances attributed to plasmonic effects are shown to broaden the emission spectra significantly, when electrons are excited along a direction where the plasma size is smaller than the plasma wavelength. We demonstrate that such resonances can be turned on and off by changing the polarization properties of elliptically-shaped driving laser-pulses. Both 3D Maxwell consistent simulations and experimental results confirm that a significant THz pulse shortening and spectral broadening can be achieved by exploiting the transverse driving laser-beam shape as an additional degree of freedom.

Cross-lists for Tue, 20 Mar 18

[5]  arXiv:1706.04689 (cross-list from physics.chem-ph) [pdf]
Title: Direct measurements of DOCO isomers in the kinetics of OD+CO
Comments: 19 pages, 4 figures
Subjects: Chemical Physics (physics.chem-ph); Optics (physics.optics)

Quantitative and mechanistically-detailed kinetics of the reaction of hydroxyl radical (OH) with carbon monoxide (CO) have been a longstanding goal of contemporary chemical kinetics. This fundamental prototype reaction plays an important role in atmospheric and combustion chemistry, motivating studies for accurate determination of the reaction rate coefficient and its pressure and temperature dependence at thermal reaction conditions. This intricate dependence can be traced directly to details of the underlying dynamics (formation, isomerization, and dissociation) involving the reactive intermediates cis- and trans-HOCO, which can only be observed transiently. Using time-resolved frequency comb spectroscopy, comprehensive mechanistic elucidation of the kinetics of the isotopic analogue deuteroxyl radical (OD) with CO has been realized. By monitoring the concentrations of reactants, intermediates, and products in real-time, the branching and isomerization kinetics and absolute yields of all species in the OD+CO reaction are quantified as a function of pressure and collision partner.

[6]  arXiv:1803.06515 (cross-list from quant-ph) [pdf, ps, other]
Title: From nonholonomic quantum constraint to canonical variables of photons I: true intrinsic degree of freedom
Comments: 18 pages, 1 figure
Subjects: Quantum Physics (quant-ph); Representation Theory (math.RT); Optics (physics.optics)

We report that the true intrinsic degree of freedom of the photon is neither the polarization nor the spin. It describes a local property in momentum space and is represented in the local representation by the Pauli matrices. This result is achieved by treating the transversality condition on the vector wavefunction as a nonholonomic quantum constraint. We find that the quantum constraint makes it possible to generalize the Stokes parameters to characterize the polarization of a general state. Unexpectedly, the generalized Stokes parameters are specified in a momentum-space local reference system that is fixed by another degree of freedom, called Stratton vector. Only constant Stokes parameters in one particular local reference system can convey the intrinsic degree of freedom of the photon. We show that the optical rotation is one of such processes that change the Stratton vector with the intrinsic quantum number remaining fixed. Changing the Stratton vector of the eigenstate of the helicity will give rise to a Berry's phase.

[7]  arXiv:1803.06767 (cross-list from quant-ph) [pdf, other]
Title: Generation and detection of non-Gaussian phonon-added coherent states in optomechanical systems
Comments: 5+4 pages, 3+1 figures
Subjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Optics (physics.optics)

Adding excitations on a coherent state provides an effective way to observe nonclassical properties of radiation fields. Here we describe and analyse how to apply this concept to the motional state of a mechanical oscillator and present a full scheme to prepare non-Gaussian {\it phonon}-added coherent states of the mechanical motion in cavity optomechanics. We first generate a mechanical coherent state using electromagnetically induced transparency. We then add a single phonon onto the coherent state via optomechanical parametric down-conversion combined with single photon detection. We validate this single-phonon-added coherent state by using a red-detuned beam and reading out the state of the optical output field. This approach allows us to verify nonclassical properties of the phonon state, such as sub-Poissonian character and quadrature squeezing. We further show that our scheme can be directly implemented using existing devices, and is generic in nature and hence applicable to a variety of systems in opto- and electromechanics.

[8]  arXiv:1803.06809 (cross-list from quant-ph) [pdf, ps, other]
Title: Absorption interferometer based on phase modulation
Authors: Miaodi Guo, Xuemei Su
Comments: 6 pages, 5 figures
Subjects: Quantum Physics (quant-ph); Optics (physics.optics)

We propose a scheme in which an arbitrary incidence can be made perfectly reflected/transmitted if a phase setup is adjusted under a specific condition. We analyze the intracavity field variation as well as the output field with changing closed-loop phase of atomic system and relative phase of input probe beams. And we obtain the condition for perfect transmitter or reflector. By adjusting two phase setups, the medium absorption and light interference can be controlled so that photon escape from cavity can be modulated, thus the intensity switching based on phase control can be realized. Then based on the transmission/reflection analysis, total absorption of this system can be investigated. Therefore our scheme can be used as an absorption interferometer to explore the optical absorption in some complicated system. The phase delay dependent on phi_1 or phi_2 in output light intensity can be applied in the realization of quantum phase gate and subtle wave filter. And based on this scheme, we implement the state transfer between perfect transmitter/reflector and non-perfect coherent photon absorber via relative-phase modulation.

[9]  arXiv:1803.06868 (cross-list from physics.plasm-ph) [pdf, other]
Title: Generation of ten kilotesla longitudinal magnetic fields in ultraintense laser-solenoid target interactions
Comments: 5 pages, 4 figures
Subjects: Plasma Physics (physics.plasm-ph); Optics (physics.optics)

Production of the huge longitudinal magnetic fields by using an ultraintense laser pulse irradiating a solenoid target is considered. Through three-dimensional particle-in-cell simulations, it is shown that the longitudinal magnetic field up to ten kilotesla can be observed in the ultraintense laser-solenoid target interactions. The finding is associated with both fast and return electron currents in the solenoid target. The huge longitudinal magnetic field is of interest for a number of important applications, which include controlling the divergence of laser-driven energetic particles for medical treatment, fast-ignition in inertial fusion, etc., as an example, the well focused and confined directional electron beams are realized by using the solenoid target.

[10]  arXiv:1803.06954 (cross-list from physics.chem-ph) [pdf]
Title: Spectral analyses of trans- and cis-DOCO transients via comb spectroscopy
Comments: 4 figures, 3 tables
Subjects: Chemical Physics (physics.chem-ph); Optics (physics.optics)

We use time-resolved direct frequency comb spectroscopy in the mid-infrared to obtain high-resolution rovibrational spectra of products produced from the OD+CO reaction. In this work, we present spectral analyses for isotopologues of the transient DOCO radicals from this reaction in the OD stretch region. The analyses were performed with aid of two different theoretical approaches based on both perturbation theory and variational calculations used for prediction of rovibrational spectra of polyatomic molecules. We discuss the advantages and challenges of our current approach for studying spectroscopy and dynamics of transient molecules.

[11]  arXiv:1803.07014 (cross-list from quant-ph) [pdf, other]
Title: Two-photon interference in the telecom C-band after frequency conversion of photons from remote quantum emitters
Authors: Jonas H. Weber (1), Benjamin Kambs (2), Jan Kettler (1), Simon Kern (1), Julian Maisch (1), Hüseyin Vural (1), Michael Jetter (1), Simone L. Portalupi (1), Christoph Becher (2), Peter Michler (1) ((1) Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany, (2) Fachrichtung Physik, Universität des Saarlandes, Campus E 2.6, 66123 Saarbrücken, Germany)
Comments: J. H. Weber and B. Kambs contributed equally to this work
Subjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Applied Physics (physics.app-ph); Optics (physics.optics)

Efficient fiber-based long-distance quantum communication via quantum repeaters relies on deterministic single-photon sources at telecom wavelengths, with the potential to exploit the existing world-wide infrastructures. For upscaling the experimental complexity in quantum networking, two-photon interference (TPI) of remote non-classical emitters in the low-loss telecom bands is of utmost importance. With respect to TPI of distinct emitters, several experiments have been conducted, e.g., using trapped atoms [Beugnon2006], ions [Maunz2007], NV-centers [Bernien2012, Sipahigil2012], SiV-centers [Sipahigil2014], organic molecules [Lettow2010] and semiconductor quantum dots (QDs) [Patel2010, Flagg2010, He2013b, Gold2014, Giesz2015, Thoma2017, Reindl2017, Zopf2017]; however, the spectral range was far from the highly desirable telecom C-band. Here, we report on TPI at 1550 nm between down-converted single photons from remote QDs [Michler2017Book], demonstrating quantum frequency conversion [Zaske2012, Ates2012, Kambs2016] as precise and stable mechanism to erase the frequency difference between independent emitters. On resonance, a TPI-visibility of (29+-3)% has been observed, being only limited by spectral diffusion processes of the individual QDs [Robinson2000, Kuhlmann2015]. Up to 2-km of additional fiber channel has been introduced in both or individual signal paths with no influence on TPI-visibility, proving negligible photon wave-packet distortion. The present experiment is conducted within a local fiber network covering several rooms between two floors of the building. Our studies pave the way to establish long-distance entanglement distribution between remote solid-state emitters including interfaces with various quantum hybrid systems [DeGreve2012,Maring2017,Bock2017,Maring2018].

Replacements for Tue, 20 Mar 18

[12]  arXiv:1706.06263 (replaced) [pdf]
Title: Dynamical characteristics of electromagnetic field under conditions of total reflection
Comments: 19 pages, 4 figures
Journal-ref: J. Opt. 20, No 4, 045604 (2018)
Subjects: Optics (physics.optics)
[13]  arXiv:1711.04227 (replaced) [pdf, other]
Title: Phase-and-amplitude recovery from a single phase contrast image using partially spatially coherent X-ray radiation
Subjects: Optics (physics.optics)
[14]  arXiv:1706.06747 (replaced) [pdf, ps, other]
Title: Bounds on quantum confinement effects in metal nanoparticles
Comments: 11 pages, 6 figures
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Optics (physics.optics)
[15]  arXiv:1711.05450 (replaced) [pdf, ps, other]
Title: Scattering Theory and $\mathcal{P}\mathcal{T}$-Symmetry
Authors: Ali Mostafazadeh
Comments: Slightly expanded revised version, 38 pages
Subjects: Quantum Physics (quant-ph); Mathematical Physics (math-ph); Optics (physics.optics)
[16]  arXiv:1712.08275 (replaced) [pdf, ps, other]
Title: Ultracold anions for high-precision antihydrogen experiments
Comments: 5 pages, 4 figures
Subjects: Atomic Physics (physics.atom-ph); Optics (physics.optics); Quantum Physics (quant-ph)
[17]  arXiv:1803.03447 (replaced) [pdf, other]
Title: Probability of radiation of twisted photons in the infrared domain
Comments: 26 pp., 7 figs; formulas (15)-(22) added
Subjects: Accelerator Physics (physics.acc-ph); Optics (physics.optics)
[ total of 17 entries: 1-17 ]
[ showing up to 2000 entries per page: fewer | more ]

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