Diffraction Enhanced Transparency and Slow THz Light in Periodic Arrays of Detuned and Displaced Dipoles

Schaafsma, Martijn C.; Bhattacharya, Arkabrata; Rivas, Jaime Gómez

doi:10.1021/acsphotonics.6b00121

Cited by 42 publications

(41 citation statements)

References 47 publications

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“…SLRs define a cavity mode with a much longer lifetime than LSPRs due to destructive interference of light scattered to the far field and the redistribution of the near field farther from the metal surface, which results in a reduction of the Ohmic losses . The energy and quality factor of the SLRs can be tuned by changing the size of the particles, the lattice dimensions, and the number of particles in the unit cell …”

Section: Plasmonic Nanoparticle Arraysmentioning

confidence: 99%

Enhanced Delayed Fluorescence in Tetracene Crystals by Strong Light‐Matter Coupling

Berghuis

Halpin

Le‐Van

et al. 2019

Adv Funct Materials

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An enhanced delayed fluorescence is demonstrated experimentally in tetracene single crystals strongly coupled to optical modes in open cavities formed by arrays of plasmonic nanoparticles. Hybridization of singlet excitons with collective plasmonic resonances in the arrays leads to the splitting of the material dispersion into a lower and an upper polariton band. This splitting significantly modifies the dynamics of the photoexcited tetracene crystal, resulting in an increase of the delayed fluorescence by a factor of 4. The enhanced delayed fluorescence is attributed to the emergence of an additional radiative decay channel, where the lower polariton band harvests long-lived triplet states. There is also an increase in total emission, which is wavelength dependent, and can be explained by the direct emission from the lower polariton band, the more efficient light out-coupling, and the enhancement of the excitation intensity. The observed enhanced fluorescence opens the possibility of efficient radiative triplet harvesting in open optical cavities, to improve the performance of organic light emitting diodes. and organic photovoltaics (OPV). The performance of these devices is determined by properties such as absorption and emission cross-section, chemical reactivity, and excited state dynamics, arising from the potential energy surface of the molecules. [1,2] Hence, controlling the energy surface can provide a remarkable impact on photophysical processes involved in these devices. Tuning of the properties of organic materials is usually done through chemical synthesis. However, changing the molecular composition might also affect the processability and morphology of thin films fabricated from the molecules, which may be detrimental for the performance.Recently, an alternative method has emerged to modify the energy surfaces of molecules and to alter their properties without changing the molecular composition: strong light-matter coupling. Theoretical developments continue to uncover the physics underpinning changes to the potential energy surfaces of molecules in this regime, [3][4][5] with tremendous implications for the photophysical properties of organic materials. Strong coupling between photons in optical cavities and excitons in semiconductors results in hybrid quasi-particles called exciton-polaritons. The strong coupling leads to an avoided crossing between the dispersions of cavity photons and excitons at the energy and momentum at which they would overlap. This coupling leads to the splitting in energy of the dispersion into the lower polariton band (LPB) and the upper polariton band (UPB). The width of the splitting between these bands is determined by the coupling strength and is called the Rabi energy. The properties of these hybrid quasi-particles are a combination of the properties of the two uncoupled states (bare states). [6] This remarkable consequence of strong coupling has led to the possibility of tuning the properties of materials, such as exciton transport, [7][8][9][10] conductivity, [11] ...

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Section: Plasmonic Nanoparticle Arraysmentioning

confidence: 99%

Enhanced Delayed Fluorescence in Tetracene Crystals by Strong Light‐Matter Coupling

Berghuis

Halpin

Le‐Van

et al. 2019

Adv Funct Materials

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“…For example, this increases the resonance Q-factors of a simple split ring wire resonator supporting an inductive-capacitive (LC) mode and a quadrupole mode. Lattice mode coupling is very versatile and has been demonstrated on different types of metamaterial [35][36][37][38][39]41,42] and plasmonic resonances [16][17][18]34,43,[60][61][62][63][64][65][66][67][68][69][70][71][72]. This review highlights the SLR coupling to LC, dipole and hybridized modes of metamaterial resonators.…”

Section: High-q Resonancesmentioning

confidence: 99%

“…Within the transparency window, light experiences an anomalous phase change because of a steep dispersion. The induced steep dispersion of the medium can slow the propagation of light pulses by several orders of magnitude [41,[81][82][83] and enhances nonlinear interactions [84]. Such narrow and highly dispersive transparency windows possess a high Q-factor and are a promising platform for sensing and nonlinear applications.…”

Section: Lattice-induced Transparency (Lit)mentioning

confidence: 99%

“…SLRs could be used to couple with the eigen or coupled resonances of metamaterial structures to show very interesting effects. These effects include extraordinary transmission, reduction of radiative losses for high quality (Q) factor resonances, electromagnetically induced transparency and strong coupling physics between SLRs and metamaterial resonances [35][36][37][38][39][40][41][42][43]. For a long time, the terahertz region of electromagnetic spectrum was being referred to as technological gap between the infrared and microwave frequencies, which required more efficient and compact terahertz devices, sources and detectors [44].…”

Section: Introductionmentioning

confidence: 99%

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Surface Lattice Resonances in THz Metamaterials

2019

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Diffraction of light in periodic structures is observed in a variety of systems including atoms, solid state crystals, plasmonic structures, metamaterials, and photonic crystals. In metamaterials, lattice diffraction appears across microwave to optical frequencies due to collective Rayleigh scattering of periodically arranged structures. Light waves diffracted by these periodic structures can be trapped along the metamaterial surface resulting in the excitation of surface lattice resonances, which are mediated by the structural eigenmodes of the metamaterial cavity. This has brought about fascinating opportunities such as lattice-induced transparency, strong nearfield confinement, and resonant field enhancement and line-narrowing of metamaterial structural resonances through lowering of radiative losses. In this review, we describe the mechanisms and implications of metamaterial-engineered surface lattice resonances and lattice-enhanced field confinement in terahertz metamaterials. These universal properties of surface lattice resonances in metamaterials have significant implications for the design of resonant metamaterials, including ultrasensitive sensors, lasers, and slow-light devices across the electromagnetic spectrum.

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“…The dolmens are arranged in a periodic lattice, where the response to the incident electromagnetic radiation is enhanced by diffraction. Recently, the combination of radiative and near-field couplings has drawn attention in this respect, for demonstrating DET in split-ring resonator (SRR) arrays [10], and pairs of detuned dipoles [11], as well as for exciting radiant antisymmetric collective resonances in near-field coupled structures [12].…”

Section: Introductionmentioning

confidence: 99%

Terahertz diffraction enhanced transparency probed in the near field

et al. 2017

Self Cite

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Electromagnetically induced transparency in metamaterials allows to engineer structures which transmit narrow spectral ranges of radiation while exhibiting a large group index. Implementation of this phenomenon frequently calls for strong near-field coupling of bright (dipolar) resonances to dark (multipolar) resonances in the metamolecules comprising the metamaterials. The sharpness and contrast of the resulting transparency windows thus depends strongly on how closely these metamolecules can be placed to one another, placing constraints on fabrication capabilities. In this manuscript, we demonstrate that the reliance on near-field interaction strength can be relaxed, and the magnitude of the electromagnetic-induced transparency enhanced, by exploiting the long-range coupling between metamolecules in periodic lattices. By placing dolmen structures resonant at THz frequencies in a periodic lattice, we show a significant increase of the transparency window when the in-plane diffraction is tuned to the resonant frequency of the metamolecules, as confirmed by direct mapping of the THz near-field amplitude across a lattice of dolmens. Through the direct interrogation of the dark resonance in the near field, we show the interplay of near-and far-field couplings in optimizing the response of planar dolmen arrays via diffraction-enhanced transparency.

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Diffraction Enhanced Transparency and Slow THz Light in Periodic Arrays of Detuned and Displaced Dipoles

Cited by 42 publications

References 47 publications

Enhanced Delayed Fluorescence in Tetracene Crystals by Strong Light‐Matter Coupling

Enhanced Delayed Fluorescence in Tetracene Crystals by Strong Light‐Matter Coupling

Surface Lattice Resonances in THz Metamaterials

Terahertz diffraction enhanced transparency probed in the near field

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