1,043 research outputs found
Coherent Control of Quantum Dynamics with Sequences of Unitary Phase-Kick Pulses
Coherent optical control schemes exploit the coherence of laser pulses to
change the phases of interfering dynamical pathways in order to manipulate
dynamical processes. These active control methods are closely related to
dynamical decoupling techniques, popularized in the field of Quantum
Information. Inspired by Nuclear Magnetic Resonance (NMR) spectroscopy,
dynamical decoupling methods apply sequences of unitary operations to modify
the interference phenomena responsible for the system dynamics thus also
belonging to the general class of coherent control techniques. Here we review
related developments in the fields of coherent optical control and dynamical
decoupling, with emphasis on control of tunneling and decoherence in general
model systems. Considering recent experimental breakthroughs in the
demonstration of active control of a variety of systems, we anticipate that the
reviewed coherent control scenarios and dynamical decoupling methods should
raise significant experimental interest.Comment: 52 pages, 7 figure
Nonlinear acousto-magneto-plasmonics
We review the recent progress in experimental and theoretical research of
interactions between the acoustic, magnetic and plasmonic transients in hybrid
metal-ferromagnet multilayer structures excited by ultrashort laser pulses. The
main focus is on understanding the nonlinear aspects of the acoustic dynamics
in materials as well as the peculiarities in the nonlinear optical and
magneto-optical response. For example, the nonlinear optical detection is
illustrated in details by probing the static magneto-optical second harmonic
generation in gold-cobalt-silver trilayer structures in Kretschmann geometry.
Furthermore, we show experimentally how the nonlinear reshaping of giant
ultrashort acoustic pulses propagating in gold can be quantified by
time-resolved plasmonic interferometry and how these ultrashort optical pulses
dynamically modulate the optical nonlinearities. The effective medium
approximation for the optical properties of hybrid multilayers facilitates the
understanding of novel optical detection techniques. In the discussion we
highlight recent works on the nonlinear magneto-elastic interactions, and
strain-induced effects in semiconductor quantum dots.Comment: 30 pages, 12 figures, to be published as a Topical Review in the
Journal of Optic
A review: Concept of Localized Surface Plasmon Enhanced Second- Harmonic Generation in Semiconductor- Metal Hybrid Nanostructures
Semiconductor-metal hybrid nanostructures and potential applications ranging optical sensing , photocatalysis and optical devices have brought interest due to a singular localized surface plasmon (LSP) effect for optical enhancement .LSPs in metal surface, excited by the interaction between light and electron plasma waves, are capable of introducing an enhanced local electromagnetic-field, which has a great enhancement on a variety of optical processes spatially enhanced optical second-harmonic generation. This review article introduces a comprehensive seeing of physical mechanisms of optical second harmonic generation (SHG) in semiconductor metal hybrid nanostructures, and the enhancement of SHG by means of localized surface plasmon. This article includes the basic concept of; optical properties of semiconductor nanomaterials, Localized Surface Plasmon (LSP) , Hybrid Nanomaterials (HNs) (which include optical properties of hybrid nanostructures, motivation of hybrid nanostructures and the synthesis method of hybrid nanostructures), nonlinear optics properties which include , nonlinear optics properties of materials, second –harmonic generation SHG in semiconductor materials and the principles of enhance second – harmonic generation SHG effect
Momentum alignment and the optical valley Hall effect in low-dimensional Dirac materials
We study the momentum alignment phenomenon and the optical control of valley
population in gapless and gapped graphene-like materials. We show that the
trigonal warping effect allows for the spatial separation of carriers belonging
to different valleys via the application of linearly polarized light. Valley
separation in gapped materials can be detected by measuring the degree of
circular polarization of band-edge photoluminescence at different sides of the
sample or light spot (optical valley Hall effect). We also show that the
momentum alignment phenomenon leads to the giant enhancement of near-band-edge
interband optical transitions in narrow-gap carbon nanotubes and graphene
nanoribbons independent of the mechanism of the gap formation. A detection
scheme to observe these giant interband transitions is proposed which opens a
route for creating novel terahertz radiation emitters.Comment: 28 pages, 9 figure
Computing Optical Properties of Ultra-thin Crystals
An overview is given of recent advances in experimental and theoretical
understanding of optical properties of ultra-thin crystal structures (graphene,
phosphorene, silicene, MoS2, MoSe2 , WS2 , WSe2 , h-AlN, h-BN, fluorographene,
graphane). Ultra-thin crystals are atomically-thick layered crystals that have
unique properties which differ from their 3D counterpart. Because of the
difficulties in the synthesis of few-atom-thick crystal structures, which are
thought to be the main building blocks of future nanotechnology, reliable
theoretical predictions of their electronic, vibrational and optical properties
are of great importance. Recent studies revealed the reliable predictive power
of existing theoretical approaches based on density functional theory (DFT)
NIR-emissive Alkynylplatinum(II) Terpyridyl Complex as a turn-on selective probe for heparin quantification by induced helical self-assembly behaviour
The extent of self-assembly viametal–metal and π-π stacking interactions, induced by the polyanionic biopolymers, enables the class of alkynylplatinum(II) terpyridyl complexes to be applicable for the sensing of important biomacromolecules through the monitoring of spectral changes. Strong demand arises for the design of selective and practical detection techniques for the quantification of heparin, a highly negative-charged polysaccharidethat can function as anticoagulant, due to the prevention of hemorrhagic complications upon overdose usage.Aconvenient sensing protocol for the detection of UFH and LMWH, two common forms of heparins in clinical use, in buffer and biological medium has been demonstrated with the spectral changes associated with the induced self-assembly of a NIR-emissive platinum(II) complex. The detection range has been demonstrated to cover clinical dosage levels and the structurally similar analogues can be effectively differentiated based on their anionic charge density and the formation of supramolecular helical assembly of the platinum(II) complex with them ...postprin
Amphiphilic Anionic Pt(II) Complexes: from spectroscopic to morphological changes
A new class of amphiphilic anionic platinum(II) bzimpy complexes has been demonstrated to show aggregation in water through PtfflfflfflPt and π–π stacking interactions. An interesting aggregation–partial deaggregation–aggregation process and a morphological transformation from vesicles to nanofibers have been demonstrated. These changes can be systematically controlled by the variation of solvent composition and could readily be probed by UV-vis absorption, emission, NMR, transmission electron microscopy and even with our naked eyes ...postprin
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