| 1. |
- Baranov, Denis, 1990, et al.
(författare)
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All-dielectric nanophotonics: the quest for better materials and fabrication techniques
- 2017
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Ingår i: Optica. - : The Optical Society. - 2334-2536. ; 4:7, s. 814-825
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Forskningsöversikt (refereegranskat)abstract
- All-dielectric nanophotonics is an exciting and rapidly developing area of nano-optics that utilizes the resonant behavior of high-index low-loss dielectric nanoparticles to enhance light-matter interaction at the nanoscale. When experimental implementation of a specific all-dielectric nanostructure is desired, two crucial factors have to be considered: the choice of a high-index material and a fabrication method. The degree to which various effects can be enhanced relies on the dielectric response of the chosen material as well as the fabrication accuracy. Here, we provide an overview of available high-index materials and existing fabrication techniques for the realization of all-dielectric nanostructures. We compare performance of the chosen materials in the visible and IR spectral ranges in terms of scattering efficiencies and Q factors of the magnetic Mie resonance. Methods for all-dielectric nanostructure fabrication are discussed and their advantages and disadvantages are highlighted. We also present an outlook for the search for better materials with higher refractive indices and novel fabrication methods that will enable low-cost manufacturing of optically resonant high-index nanoparticles. We believe that this information will be valuable across the field of nanophotonics and particularly for the design of resonant all-dielectric nanostructures.
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| 2. |
- Baranov, Denis, 1990, et al.
(författare)
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Nanophotonic engineering of far-field thermal emitters
- 2019
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122. ; 18:9, s. 920-930
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Forskningsöversikt (refereegranskat)abstract
- Thermal emission is a ubiquitous and fundamental process by which all objects at non-zero temperatures radiate electromagnetic energy. This process is often assumed to be incoherent in both space and time, resulting in broadband, omnidirectional light emission toward the far field, with a spectral density related to the emitter temperature by Planck’s law. Over the past two decades, there has been considerable progress in engineering the spectrum, directionality, polarization and temporal response of thermally emitted light using nanostructured materials. This Review summarizes the basic physics of thermal emission, lays out various nanophotonic approaches to engineer thermal emission in the far field, and highlights several applications, including energy harvesting, lighting and radiative cooling.
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| 3. |
- Baranov, Denis, 1990, et al.
(författare)
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Coherent perfect absorbers: Linear control of light with light
- 2017
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Ingår i: Nature Reviews Materials. - : Springer Science and Business Media LLC. - 2058-8437. ; 2
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Forskningsöversikt (refereegranskat)abstract
- The absorption of electromagnetic energy by a material is a phenomenon that underlies many applications, including molecular sensing, photocurrent generation and photodetection. Typically, the incident energy is delivered to the system through a single channel, for example, by a plane wave incident on one side of an absorber. However, absorption can be made much more efficient by exploiting wave interference. A coherent perfect absorber is a system in which the complete absorption of electromagnetic radiation is achieved by controlling the interference of multiple incident waves. Here, we review recent advances in the design and applications of such devices. We present the theoretical principles underlying the phenomenon of coherent perfect absorption and give an overview of the photonic structures in which it can be realized, including planar and guided-mode structures, graphene-based systems, parity-symmetric and time-symmetric structures, 3D structures and quantum-mechanical systems. We then discuss possible applications of coherent perfect absorption in nanophotonics, and, finally, we survey the perspectives for the future of this field.
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| 4. |
- Baranov, Denis, 1990, et al.
(författare)
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Modifying magnetic dipole spontaneous emission with nanophotonic structures
- 2017
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Ingår i: Laser and Photonics Reviews. - : Wiley. - 1863-8899 .- 1863-8880. ; 11:3, s. Article Number: 1600268-
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Forskningsöversikt (refereegranskat)abstract
- Tailoring of electromagnetic spontaneous emission predicted by E. M. Purcell more than 50 years ago has undoubtedly proven to be one of the most important effects in the rich areas of quantum optics and nanophotonics. Although during the past decades the research in this field has been focused on electric dipole emission, the recent progress in nanofabrication and study of magnetic quantum emitters, such as rare-earth ions, has stimulated the investigation of the magnetic side of spontaneous emission. Here, we review the state-of-the-art advances in the field of spontaneous emission enhancement of magnetic dipole quantum emitters with the use of various nanophotonics systems. We provide the general theory describing the Purcell effect of magnetic emitters, overview realizations of specific nanophotonics structures allowing for the enhanced magnetic dipole spontaneous emission, and give an outlook on the challenges in this field, which remain open to future research.
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| 5. |
- Krasnok, A. E., et al.
(författare)
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Virtual electromagnetic absorption and energy storage by a Hermitian system via complex frequency excitation
- 2017
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Ingår i: 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings. ; Part F42-CLEO_QELS 2017, s. paper FM1G.3-
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Konferensbidrag (refereegranskat)abstract
- Hermitian systems, with no Ohmic loss, support virtual absorbing modes located in the complex frequency plane. Although being usually considered non-physical due to their divergent exponential time dependence, these modes play a crucial role in the overall scattering response. Here, we access these modes and use them for virtual absorption and storage of light by specifically shaping the incident excitation with exponentially growing envelopes.
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| 6. |
- Savelev, R. S., et al.
(författare)
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Dynamically reconfigurable metal-semiconductor Yagi-Uda nanoantenna
- 2017
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Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 95:23, s. Article Number: 235409-
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically investigate the properties of a tunable Yagi-Uda nanoantenna composed of metal-dielectric (Ag-Ge) core-shell nanoparticles. We show that, due to the combination of two types of resonances in each nanoparticle, such hybrid Yagi-Uda nanoantenna can operate in two different regimes. Besides the conventional nonresonant operation regime at low frequencies, characterized by highly directive emission in the forward direction, there is another one at higher frequencies caused by a hybrid magneto-electric response of the core-shell nanoparticles. This regime is based on the excitation of the van Hove singularity, and emission in this regime is accompanied by high values of directivity and Purcell factor within the same narrow frequency range. Our analysis reveals the possibility of flexible dynamical tuning of the hybrid nanoantenna emission pattern via electron-hole plasma excitation by 100 fs pump pulse with relatively low peak intensities similar to 200 MWcm(-2).
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| 7. |
- Savelev, R.S., et al.
(författare)
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Nonlinear core-shell yagi-uda nanoantenna for highly tunable directive emission
- 2017
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Ingår i: 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings. - 9781943580279 ; Part F43-CLEO_AT 2017
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Konferensbidrag (refereegranskat)abstract
- We propose a novel type of tunable Yagi-Uda nanoantenna composed of metal-dielectric (Ag- Ge) core-shell nanoparticles. By choosing the appropriate nanoantenna parameters we excite a Van Hove singularity, supporting high values of directivity and Purcell factor within the same narrow frequency range. Our analysis reveals the possibility of flexible dynamical tuning of the hybrid nanoantenna emission pattern via electron-hole plasma excitation by additional fs-laser signal pulses.
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| 8. |
- Baranov, Denis, 1990, et al.
(författare)
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Coherent virtual absorption based on complex zero excitation for ideal light capturing
- 2017
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Ingår i: Optica. - : The Optical Society. - 2334-2536. ; 4:12, s. 1457-1461
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Tidskriftsartikel (refereegranskat)abstract
- Absorption of light is directly associated with dissipative processes in a material. In suitably tailored resonators, a specific level of dissipation can support coherent perfect absorption, the time-reversed analogue of lasing, which enables total absorption and zero scattering in open cavities. On the contrary, the scattering zeros of lossless objects strictly occur at complex frequencies. While usually considered nonphysical due to their divergent response in time, these zeros play a crucial role in the overall scattering dispersion. Here, we introduce the concept of coherent virtual absorption, accessing these modes by temporally shaping the incident waveform. We show that engaging these complex zeros enables storing and releasing the electromagnetic energy at will within a lossless structure for arbitrary amounts of time, under the control of the impinging field. The effect is robust with respect to inevitable material dissipation and can be realized in systems with any number of input ports. The observed effect may have important implications for flexible control of light propagation and storage, low-energy memory, and optical modulation. (c) 2017 Optical Society of America
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| 9. |
- Krasnok, A. E., et al.
(författare)
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All-Dielectric Nanophotonics: Fundamentals, Fabrication, and Applications
- 2018
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Ingår i: World Scientific Series in Nanoscience and Nanotechnology. - : World Scientific. - 2301-301X .- 2335-6693. ; , s. 337-385
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter reviews a novel, rapidly developing field of modern light science named all-dielectric nanophotonics. This branch of nanophotonics is based on the properties of high-index dielectric nanoparticles which allow for controlling both magnetic and electric responses of a nanostructured matter. Here, we discuss optical properties of high-index dielectric nanoparticles, methods of their fabrication, and recent advances in practical applications, including the quantum source emission engineering, Fano resonances in all-dielectric nanoclusters, surface enhanced spectroscopy and sensing, coupled-resonator optical waveguides, metamaterials and metasurfaces, and nonlinear nanophotonics.
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| 10. |
- Krasnok, A. E., et al.
(författare)
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All-Optical Switching and Unidirectional Plasmon Launching with Nonlinear Dielectric Nanoantennas
- 2018
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Ingår i: Physical Review Applied. - 2331-7019. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- High-index dielectric nanoparticles have become a powerful platform for nonlinear nanophotonics due to special types of optical nonlinearity, e.g. caused by electron-hole plasma (EHP) photoexcitation. We propose a highly tunable dielectric nanoantenna consisting of a chain of silicon particles excited by a dipole emitter. The nanoantenna exhibits slow group-velocity guided modes, corresponding to the Van Hove singularity in an infinite structure, which enable a large Purcell factor up to several hundred and are very sensitive to the nanoparticle permittivity. This sensitivity enables the nanoantenna tuning via EHP excitation with an ultrafast laser pumping. Dramatic variations in the nanoantenna radiation patterns and Purcell factor caused by ultrafast laser pumping of several boundary nanoparticles with relatively low intensities of about 25 GW/cm2 are shown. Unidirectional surface-plasmon polaritons launching with EHP excitation in the nanoantenna on a Ag substrate is demonstrated.
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