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Alberto G. Curto

Alberto G. Curto
Ghent University and imec

Professor
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About

55
Publications
16,926
Reads
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3,102
Citations
Additional affiliations
July 2016 - present
TU/e Eindhoven University of Technology
Position
  • Professor (Assistant)
August 2013 - July 2016
Stanford University
Position
  • PostDoc Position
February 2008 - May 2013
ICFO Institute of Photonic Sciences
Position
  • PhD
Education
February 2008 - September 2009
September 2002 - July 2007
Universidad de Salamanca
Field of study
  • Physics

Publications

Publications (55)
Article
Full-text available
By directing light, optical antennas can enhance light-matter interaction and improve the efficiency of nanophotonic devices. Here we exploit the interference between the electric dipole, quadrupole and magnetic dipole moments of a split-ring resonator to experimentally realize a compact directional optical antenna. This single-element antenna desi...
Article
Full-text available
The ability to detect light over a broad spectral range is central to practical optoelectronic applications and has been successfully demonstrated with photodetectors of two-dimensional layered crystals such as graphene and MoS2. However, polarization sensitivity within such a photodetector remains elusive. Here, we demonstrate a broadband photodet...
Article
Full-text available
Controlling light emission from quantum emitters has important applications ranging from solid-state lighting and displays to nanoscale single-photon sources. Optical antennas have emerged as promising tools to achieve such control right at the location of the emitter, without the need for bulky, external optics. Semiconductor nanoantennas are part...
Article
Full-text available
The interaction of circularly polarized light with matter is the basis for molecular circular dichroism spectroscopy, optical spin manipulation, and optical torques. However, chiroptical effects are usually hampered by weak chiral light-matter interaction. Nanophotonic structures can enhance optical intensity to boost interactions, but magnifying c...
Article
Full-text available
Excitons in nanoscale materials can exhibit fluorescence fluctuations. Intermittency is pervasive in zero-dimensional emitters such as single molecules and quantum dots. In contrast, two-dimensional semiconductors are generally regarded as stable light sources. Noise contains, however, valuable information about a material. Here, we demonstrate flu...
Article
Excitons spread through diffusion and interact through exciton–exciton annihilation. Nanophotonics can counteract the resulting decrease in light emission. However, conventional enhancement treats emitters as immobile and non‐interacting. It neglects exciton redistribution between regions with different enhancements and the increase in non‐radiativ...
Article
Full-text available
The discrimination of enantiomers is crucial in biochemistry. However, chiral sensing faces significant limitations due to inherently weak chiroptical signals. Nanophotonics is a promising solution to enhance sensitivity thanks to increased optical chirality maximized by strong electric and magnetic fields. Metallic and dielectric nanoparticles can...
Article
Full-text available
Using diffraction-limited ultrafast imaging techniques, we investigate the propagation of singlet and triplet excitons in single-crystal tetracene. Instead of an expected broadening, the distribution of singlet excitons narrows on a nanosecond time scale after photoexcitation. This narrowing results in an effective negative diffusion in which singl...
Conference Paper
Full-text available
The discrimination of enantiomers is crucial in biochemistry. However, chiral sensing faces significant limitations due to inherently weak chiroptical signals. Nanophotonics is a promising solution to enhance sensitivity thanks to increased optical chirality maximized by strong electric and magnetic fields. Metal nanoparticles support intense elect...
Conference Paper
Metal nanoparticles support intense electric resonances, while high-index dielectric particles offer strong magnetic resonances. Here, we propose metal-dielectric nanophotonic platforms based on duality symmetry for chiral molecular sensing.
Article
Full-text available
Beam steering is one of the main challenges in energy‐efficient and high‐speed infrared light communication. To date, active beam‐steering schemes based on a spatial light modulator (SLM) or micro‐electrical mechanical system (MEMS) mirror, as well as the passive ones based on diffractive gratings, are demonstrated for infrared light communication....
Article
Optically induced Mie resonances in dielectric nanoantennas feature low dissipative losses and large resonant enhancement of both electric and magnetic fields. They offer an alternative platform to plasmonic resonances to study light-matter interactions from the weak to the strong coupling regimes. Here, we experimentally demonstrate the strong cou...
Preprint
Full-text available
Optically induced Mie resonances in dielectric nanoantennas feature low dissipative losses and large resonant enhancement of both electric and magnetic fields. They offer an alternative platform to plasmonic resonances to study light-matter interactions from the weak to the strong coupling regimes. Here, we experimentally demonstrate the strong cou...
Preprint
Beam steering is one of the main challenges in energy-efficient and high-speed infrared light communication. To date, active beam-steering schemes based on a spatial light modulator (SLM) or micro-electrical mechanical system (MEMS) mirror, as well as the passive ones based on diffractive gratings, have been demonstrated for infrared light communic...
Preprint
Excitons spread through diffusion and interact through exciton-exciton annihilation. Nanophotonics can counteract the resulting decrease in light emission. However, conventional enhancement treats emitters as immobile and noninteracting. Here, we go beyond the localized Purcell effect to exploit exciton dynamics. As interacting excitons diffuse thr...
Preprint
Controlling the momentum of carriers in semiconductors, known as valley polarization, is a new resource for optoelectronics and information technologies. Materials exhibiting high polarization are needed for valley-based devices. Few-layer WS2 shows a remarkable spin-valley polarization above 90%, even at room temperature. In stark contrast, polari...
Article
Full-text available
An enhanced emission of high quantum yield molecules coupled to dielectric metasurfaces formed by periodic arrays of polycrystalline silicon nanoparticles is demonstrated. Radiative coupling of the nanoparticles, mediated by in‐plane diffraction, leads to the formation of collective Mie scattering resonances or Mie surface lattice resonances (M‐SLR...
Article
Full-text available
Exciton-polaritons are hybrids of light and matter formed at the strong coupling regime, that exhibit interesting phenomena such as enhanced transport, long-range energy transfer, and non-linear response. These properties make exciton-polaritons very promising quasiparticles for the development of novel optoelectronic applications in the so-called...
Article
Full-text available
The control of defect states is becoming a powerful approach to tune two-dimensional materials. Black phosphorus (BP) is a layered material that offers opportunities in infrared optoelectronics. Its band gap depends strongly on the number of layers and covers wavelengths from 720 to 4000 nm from monolayer to bulk, but only in discrete steps and suf...
Preprint
We demonstrate an enhanced emission of high quantum yield molecules coupled to dielectric metasurfaces formed by periodic arrays of polycrystalline silicon nanoparticles. Radiative coupling of the nanoparticles, mediated by in-plane diffraction, leads to the formation of collective Mie scattering resonances or Mie surface lattice resonances (M-SLRs...
Article
Full-text available
We demonstrate the strong coupling between excitons in organic molecules and all-dielectric metasurfaces formed by arrays of silicon nanoparticles supporting Mie surface lattice resonances (MSLRs). Compared to Mie resonances in individual nanoparticles, MSLRs have extended mode volumes and much larger quality factors, which enables to achieve colle...
Conference Paper
Conventional nanophotonic emission enhancement neglects excitonic phenomena of diffusion and annihilation. We go beyond the localized Purcell effect and identify the enhancement mechanisms to turn their detrimental impact into additional emission.
Article
Full-text available
Atomically thin semiconductors hold great potential for nanoscale photonic and optoelectronic devices because of their strong light absorption and emission. Despite progress, their application in integrated photonics is hindered particularly by a lack of stable layered semiconductors emitting in the infrared part of the electromagnetic spectrum. He...
Article
Full-text available
Phase-controlled synthesis of two-dimensional (2D) transition metal chalcogenides (TMCs) at low temperature with a precise thickness control has to date been rarely reported. Here, we report on a process for the phase-controlled synthesis of TiS2 (metallic) and TiS3 (semiconducting) nano-layers by atomic layer deposition (ALD) with precise thicknes...
Conference Paper
Full-text available
Atomically thin 2D layers because of their strong light interaction and integration to silicon platforms, hold great potential for integrated photonic circuit technology. Despite many progress, their application in integrated photonics is hindered particularly by a lack of stable layered semiconductors emitting in the infrared part of the electroma...
Article
Full-text available
Monolayer transition metal dichalcogenides (TMDs) are promising semiconductors for nanoscale photonics and optoelectronics due to their strong interactions with light. However, processes that integrate TMDs into nanophotonic and optoelectronic devices can introduce defects in the monolayers, resulting in lower emission efficiency. Quality control i...
Preprint
Full-text available
We demonstrate the strong coupling of direct transition excitons in tungsten disulfide (WS2) with collective plasmonic resonances at room temperature. We use open plasmonic cavities formed by periodic arrays of metallic nanoparticles. We show clear anti-crossings with monolayer, bilayer and thicker multilayer WS2 on top of the nanoparticle array. T...
Article
Full-text available
Solid state light emitters rely on metallic contacts with a high sheet-conductivity for effective charge injection. Unfortunately, such contacts also support surface plasmon polariton and lossy wave excitations that dissipate optical energy into the metal and limit the external quantum efficiency. Here, inspired by the concept of radio-frequency hi...
Article
A graphene sheet near a metal nanoantenna squeezes infrared photons into a subnanometric gap, pushing the limits of nanophotonics.
Article
Full-text available
Nanoantennas show potential for photosynthesis research for two reasons; first by spatially confining light for experiments which require high spatial resolution, and second by enhancing the photon emission of single light-harvesting complexes. For an effective use of nanoantennas a detailed understanding of the interaction between nanoantenna and...
Article
Nanostructured metallic films have the potential to replace metal oxide films as transparent electrodes in optoelectronic devices. An ideal transparent electrode should possess a high, broadband, and polarization-independent transmittance. Conventional metallic gratings and grids with wavelength-scale periodicities, however, do not have all of thes...
Article
Full-text available
The nature of the highly efficient energy transfer in photosynthetic light-harvesting complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of...
Conference Paper
form only given. By directing light, optical antennas can enhance light-matter interaction and improve the efficiency of nanophotonic devices. Though several designs have been presented1, most of them have been scaled-down radio frequency antennas which have narrow bandwidths and are sensitive to the position of the coupled emitters. Here we presen...
Thesis
Full-text available
The emission of light is at the heart of both fundamental science and technological applications. At its origin lie electronic transitions in nanoscale materials such as molecules, atoms and semiconductors. The interaction of light with such single quantum emitters is inefficient because of their point-like character. Efficient interfaces between l...
Article
Full-text available
Multipolar transitions other than electric dipoles are generally too weak to be observed at optical frequencies in single quantum emitters. For example, fluorescent molecules and quantum dots have dimensions much smaller than the wavelength of light and therefore emit predominantly as electric dipoles. Here we demonstrate controlled emission of a q...
Data
Full-text available
Supplementary Figures S1-S10, Supplementary Tables S1-S3, Supplementary Note 1 and Supplementary References
Article
Full-text available
Optical antennas offer unique possibilities for light manipulation on a sub-wavelength scale. Here, we study log-periodic antennas that exhibit broadband directivity as a result of the self-similar relation between the lengths, separations and widths of the elements. We show through numerical simulations that the log-periodic designs have a conside...
Article
Full-text available
Nanoscale quantum emitters are key elements in quantum optics and sensing. However, efficient optical excitation and detection of such emitters involves large solid angles because their interaction with freely propagating light is omnidirectional. Here, we present unidirectional emission of a single emitter by coupling to a nanofabricated Yagi-Uda...
Article
Full-text available
We address experimentally the radiation patterns of quantum dots coupled to optical nanoantennas at specific positions. We show that the emission of the coupled system is determined by a variety of resonant and non-resonant antenna modes both in polarization and angular pattern. The first working optical Yagi-Uda antenna is presented and unidirecti...
Article
Full-text available
We investigate the near-field focusing properties of three-dimensional phase antennas consisting of concentric rings designed to have source and image spots separated by several microns from the lens. Tight focal spots are obtained for silicon or gold rings patterned in a silica matrix. We analyze in detail the dependence of the performance of thes...
Article
Plasmon-mediated long-range coupling of optical excitations is shown to be attainable using near-field phase antennas involving nanoparticles situated at focal spots. The antennas rely on metal-surface features that are geometrically arranged to produce constructive interference of plasmons emanating from a source spot over a designated image posit...

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Projects

Projects (4)
Project
Fabrication, modification and optical characterization of anisotropic infrared layered semiconductors
Project
Enhancing light-matter interaction with semiconductor optical antennas