Zhang X, Khudik VN, Pukhov A, Shvets G. Laser wakefield and direct acceleration with ionization injection. Plasma Physics and Controlled Fusion [Internet]. 2016;58 :034011. Publisher's VersionAbstract
We demonstrate using particle-in-cell simulations that electrons can be injected into a hybrid laser wakefield and direct laser accelerator via ionization injection. We propose an accelerator and injector scenario that utilizes two laser pulses. The first (pump) pulse produces the plasma ‘bubble’ by expelling the plasma electrons generated by its leading edge from the low-Z component of the gas mixture, and then injects electrons into the bubble by ionizing the high-Z component. The second time-delayed laser pulse resonantly interacts with these injected electrons undergoing betatron oscillations inside the bubble. We show that the electrons ionized off-axis and on-axis but off the peak ionization phase possess sufficient transverse energy to undergo efficient direct laser acceleration (DLA). When combined with their acceleration by the bubble’s longitudinal plasma wake, DLA can double the total energy gain and produce a monoenergetic beam.
Ma T, Shvets G. All-Si valley-Hall photonic topological insulator. New Journal of Physics [Internet]. 2016;18 :025012. Publisher's VersionAbstract
An all-Si photonic structure emulating the quantum-valley-Hall effect is proposed. We show that it acts as a photonic topological insulator (PTI), and that an interface between two such PTIs can support edge states that are free from scattering. The conservation of the valley degree of freedom enables efficient in- and out-coupling of light between the free space and the photonic structure. The topological protection of the edge waves can be utilized for designing arrays of resonant time-delay photonic cavities that do not suffer from reflections and cross-talk.
Schnell M, Sarriugarte P, Neuman T, Khanikaev AB, Shvets G, Aizpurua J, Hillenbrand R. Real-Space Mapping of the Chiral Near-Field Distributions in Spiral Antennas and Planar Metasurfaces. Nano Letters [Internet]. 2016;16 :663-670. Publisher's VersionAbstract
Chiral antennas and metasurfaces can be designed to react differently to left- and right-handed circularly polarized light, which enables novel optical properties such as giant optical activity and negative refraction. Here, we demonstrate that the underlying chiral near-field distributions can be directly mapped with scattering-type scanning near-field optical microscopy employing circularly polarized illumination. We apply our technique to visualize, for the first time, the circular-polarization selective nanofocusing of infrared light in Archimedean spiral antennas, and explain this chiral optical effect by directional launching of traveling waves in analogy to antenna theory. Moreover, we near-field image single-layer rosette and asymmetric dipole–monopole metasurfaces and find negligible and strong chiral optical near-field contrast, respectively. Our technique paves the way for near-field characterization of optical chirality in metal nanostructures, which will be essential for the future development of chiral antennas and metasurfaces and their applications.
Hartsfield T, Chang W-S, Yang S-C, Ma T, Shi J, Sun L, Shvets G, Link S, Li X. Single quantum dot controls a plasmonic cavity’s scattering and anisotropy. Proceedings of the National Academy of Sciences [Internet]. 2015;112 :12288-12292. Publisher's VersionAbstract
Plasmonic cavities represent a promising platform for controlling light–matter interaction due to their exceptionally small mode volume and high density of photonic states. Using plasmonic cavities for enhancing light’s coupling to individual two-level systems, such as single semiconductor quantum dots (QD), is particularly desirable for exploring cavity quantum electrodynamic (QED) effects and using them in quantum information applications. The lack of experimental progress in this area is in part due to the difficulty of precisely placing a QD within nanometers of the plasmonic cavity. Here, we study the simplest plasmonic cavity in the form of a spherical metallic nanoparticle (MNP). By controllably positioning a semiconductor QD in the close proximity of the MNP cavity via atomic force microscope (AFM) manipulation, the scattering spectrum of the MNP is dramatically modified due to Fano interference between the classical plasmonic resonance of the MNP and the quantized exciton resonance in the QD. Moreover, our experiment demonstrates that a single two-level system can render a spherical MNP strongly anisotropic. These findings represent an important step toward realizing quantum plasmonic devices.
Arju N, Ma T, Khanikaev A, Purtseladze D, Shvets G. Optical Realization of Double-Continuum Fano Interference and Coherent Control inPlasmonic Metasurfaces. Phys. Rev. Lett. [Internet]. 2015;114 (237403). Publisher's Version
Zhang X, Khudik VN, Shvets G. Synergistic Laser-Wakefield and Direct-Laser Acceleration in the Plasma-Bubble Regime. Phys. Rev. Lett. [Internet]. 2015;114 (184801). Publisher's Version
Dabidian N, Kholmanov I, Khanikaev AB, Tatar K, Trendafilov S, Mousavi SH, Magnuson C, Ruoff RS, Shvets G. Electrical Switching of Infrared Light Using Graphene Integration with Plasmonic Fano Resonant Metasurfaces. ACS Photonics [Internet]. 2015;2 :216. Publisher's Version
Ma T, Khanikaev AB, Mousavi HS, Shvets G. Guiding Electromagnetic Waves around Sharp Corners: Topologically Protected Photonic Transport in Metawaveguides. Phys. Rev. Lett. [Internet]. 2015;114 (127401). Publisher's Version
Wu C, Arju N, Kelp G, Fan JA, Dominguez J, Gonzales E, Tutuc E, Brener I, Shvets G. Spectrally selective chiral silicon metasurfaces based on infrared Fano resonances. Nature Communications [Internet]. 2014;5 (3892). Publisher's Version
Li Z, Tsai H-E, Zhang X, Pai C-H, Chang Y-Y, Zgadzaj R, Wang X, Khudik V, Shvets G, Downer MC. Single-Shot Visualization of Evolving Laser Wakefields Using an All-Optical Streak Camera. Phys. Rev. Lett. [Internet]. 2014;113 (085001). Publisher's Version
Estep NA, Askarpour AN, Trendafilov S, Shvets G, Alu A. Transmission- Line Model and Propagation in a Negative-Index, Parallel-Plate Metamaterial to Boost Electron-Beam Interaction. IEEE Transactions on Antennas and Propagation [Internet]. 2014;62 (3212 ). Publisher's Version
Khudik V, Yi SA, Siemon C, Shvets G. The analytic model of a laser accelerated plasma target and its stability. Phys. Plasmas [Internet]. 2014;21 (013110 ). Publisher's Version
Mousavi HS, Khanikaev AB, Allen J, Allen M, Shvets G. Gyromagnetically Induced Transparency of Metasurfaces. Phys. Rev. Lett. [Internet]. 2014;112 (117402). Publisher's Version
Yi SA, Khudik V, Siemon C, Shvets G. Analytic model of electromagnetic fields around a plasma bubble in the blow-out regime. Phys. Plasma. [Internet]. 2013;20 (013108). Publisher's Version
Khanikaev AB, Mousavi HS, Tse W-K, Kargarian M, MacDonald AH, Shvets G. Photonic topological insulators. Nature Materials [Internet]. 2013;12 (233). Publisher's Version
Shafiei F, Wu C, Wu Y, Khanikaev AB, Putzke P, Singh A, Li X, Shvets G. Plasmonic nano-protractor based on polarization spectro-tomography. Nature Photonics [Internet]. 2013;7 (367). Publisher's Version
Mousavi SH, Kholmanov IN, Alici KB, Purtseladze D, Arju N, Tatar K, Fozdar DY, Suk JW, Hao Y, Khanikaev AB, et al. Inductive Tuning of Fano-Resonant Meta-Surfaces Using Plasmonic Response of Graphene in Mid-Infrared. Nano Letters [Internet]. 2013;13 (1111). Publisher's Version
Yu T-P, Pukhov A, Sheng Z-M, Liu F, Shvets G. Bright Betatronlike X Rays from Radiation Pressure Acceleration of a Mass-Limited Foil Target. Phys. Rev. Lett. [Internet]. 2013;110 (045001). Publisher's Version
Fietz C, Urzhumov Y, Shvets G. Complex k band diagrams of 3D metamaterial/photonic crystals. Optics Express [Internet]. 2012;19 (19027). Publisher's Version
III BN, Korobkin D, Ferro G, Shvets G. Prism-coupled surface wave accelerator based on silicon carbide. Phys. Rev. ST Accel. Beams [Internet]. 2012;15 (31302 ). Publisher's Version