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A Polman - One of the best experts on this subject based on the ideXlab platform.
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electron induced state conversion in diamond nv centers measured with pump probe Cathodoluminescence spectroscopy
ACS Photonics, 2020Co-Authors: Magdalena Solagarcia, Sophie Meuret, Toon Coenen, A PolmanAbstract:Nitrogen-vacancy (NV) centers in diamond are reliable single-photon emitters, with applications in quantum technologies and metrology. Two charge states are known for NV centers, NV0 and NV–, with the latter being mostly studied due to its long electron spin coherence time. Therefore, control over the charge state of the NV centers is essential. However, an understanding of the dynamics between the different states still remains challenging. Here, conversion from NV– to NV0 due to electron-induced carrier generation is shown. Ultrafast pump–probe Cathodoluminescence spectroscopy is presented for the first time, with electron pulses as pump and laser pulses as probe, to prepare and read out the NV states. The experimental data are explained with a model considering carrier dynamics (0.8 ns), NV0 spontaneous emission (20 ns), and NV0 → NV– back transfer (500 ms). The results provide new insights into the NV– → NV0 conversion dynamics and into the use of pump–probe Cathodoluminescence as a nanoscale NV chara...
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nanoscale relative emission efficiency mapping using Cathodoluminescence g 2 imaging
Nano Letters, 2018Co-Authors: Sophie Meuret, Toon Coenen, S Y Woo, A PolmanAbstract:Cathodoluminescence (CL) imaging spectroscopy provides two-dimensional optical excitation images of photonic nanostructures with a deep-subwavelength spatial resolution. So far, CL imaging was unable to provide a direct measurement of the excitation and emission probabilities of photonic nanostructures in a spatially resolved manner. Here, we demonstrate that by mapping the Cathodoluminescence autocorrelation function g(2) together with the CL spectral distribution the excitation and emission rates can be disentangled at every excitation position. We use InGaN/GaN quantum wells in GaN nanowires with diameters in the range 200–500 nm as a model system to test our new g(2) mapping methodology and find characteristic differences in excitation and emission rates both between wires and within wires. Strong differences in the average CL intensity between the wires are the result of differences in the emission efficiencies. At the highest spatial resolution, intensity variations observed within wires are the res...
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quantifying coherent and incoherent Cathodoluminescence in semiconductors and metals
Journal of Applied Physics, 2014Co-Authors: Benjamin J M Brenny, Toon Coenen, A PolmanAbstract:We present a method to separate coherent and incoherent contributions to Cathodoluminescence from bulk materials by using angle-resolved Cathodoluminescence spectroscopy. Using 5 and 30 keV electrons, we measure the Cathodoluminescence spectra for Si, GaAs, Al, Ag, Au, and Cu and determine the angular emission distributions for Al, GaAs, and Si. Aluminium shows a clear dipolar radiation profile due to coherent transition radiation, while GaAs shows incoherent luminescence characterized by a Lambertian angular distribution. Silicon shows both transition radiation and incoherent radiation. From the angular data, we determine the ratio between the two processes and decompose their spectra. This method provides a powerful way to separate different radiative Cathodoluminescence processes, which is useful for material characterization and in studies of electron- and light-matter interaction in metals and semiconductors.
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angle resolved Cathodoluminescence spectroscopy
Applied Physics Letters, 2011Co-Authors: Toon Coenen, Ernst Jan R Vesseur, A PolmanAbstract:We present a Cathodoluminescence spectroscopy technique which combines deep subwavelength excitation resolution with angle-resolved detection capabilities. The Cathodoluminescence emission is collected by a paraboloid mirror (effective NA = 0.96) and is projected onto a 2D CCD array. The azimuthal and polar emission pattern is directly deduced from the image. As proof of principle, we use the technique to measure the angular distribution of transition radiation from a single crystalline gold surface under 30 keV electron irradiation. We find that the experiment matches very well with theory, illustrating the potential of this technique for the characterization of photonic structures with deep subwavelength dimensions.
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angle resolved Cathodoluminescence spectroscopy
arXiv: Mesoscale and Nanoscale Physics, 2011Co-Authors: Toon Coenen, Ernst Jan R Vesseur, A PolmanAbstract:We present a novel Cathodoluminescence spectroscopy technique which combines a deep subwavelength excitation resolution with angle-resolved detection capabilities. The Cathodoluminescence emission is collected by a paraboloid mirror (effective NA=0.96) and is projected onto a 2D CCD array. The azimuthal and polar emission pattern is directly deduced from the image. As proof of principle we use the technique to measure the angular distribution of transition radiation from a single crystalline gold surface under 30 keV electron irradiation. We find that the experiment matches very well with theory, illustrating the potential of this new technique for the characterization of photonic structures with deep subwavelength dimensions.
Toon Coenen - One of the best experts on this subject based on the ideXlab platform.
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electron induced state conversion in diamond nv centers measured with pump probe Cathodoluminescence spectroscopy
ACS Photonics, 2020Co-Authors: Magdalena Solagarcia, Sophie Meuret, Toon Coenen, A PolmanAbstract:Nitrogen-vacancy (NV) centers in diamond are reliable single-photon emitters, with applications in quantum technologies and metrology. Two charge states are known for NV centers, NV0 and NV–, with the latter being mostly studied due to its long electron spin coherence time. Therefore, control over the charge state of the NV centers is essential. However, an understanding of the dynamics between the different states still remains challenging. Here, conversion from NV– to NV0 due to electron-induced carrier generation is shown. Ultrafast pump–probe Cathodoluminescence spectroscopy is presented for the first time, with electron pulses as pump and laser pulses as probe, to prepare and read out the NV states. The experimental data are explained with a model considering carrier dynamics (0.8 ns), NV0 spontaneous emission (20 ns), and NV0 → NV– back transfer (500 ms). The results provide new insights into the NV– → NV0 conversion dynamics and into the use of pump–probe Cathodoluminescence as a nanoscale NV chara...
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Topological photonic crystals in the visible: Design and angle-resolved characterization of the bulk and edge states
2018 Conference on Lasers and Electro-Optics (CLEO), 2018Co-Authors: Siying Peng, Nick Schilder, Xiang Ni, Sophie Meuret, Hugo Doeleman, Toon Coenen, Femius Koenderink, Alexander Khanikaev, Harry A. Atwater, Albert PolmanAbstract:We fabricated and characterized photonic crystals with non-trivial topological bulk states and pseudo-time-reversal-symmetry protected helical edge states in the visible regime. With a 30-keV electron beam, we excite coherent Cathodoluminescence in the nanostructured material and derive photonic band structures.
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nanoscale relative emission efficiency mapping using Cathodoluminescence g 2 imaging
Nano Letters, 2018Co-Authors: Sophie Meuret, Toon Coenen, S Y Woo, A PolmanAbstract:Cathodoluminescence (CL) imaging spectroscopy provides two-dimensional optical excitation images of photonic nanostructures with a deep-subwavelength spatial resolution. So far, CL imaging was unable to provide a direct measurement of the excitation and emission probabilities of photonic nanostructures in a spatially resolved manner. Here, we demonstrate that by mapping the Cathodoluminescence autocorrelation function g(2) together with the CL spectral distribution the excitation and emission rates can be disentangled at every excitation position. We use InGaN/GaN quantum wells in GaN nanowires with diameters in the range 200–500 nm as a model system to test our new g(2) mapping methodology and find characteristic differences in excitation and emission rates both between wires and within wires. Strong differences in the average CL intensity between the wires are the result of differences in the emission efficiencies. At the highest spatial resolution, intensity variations observed within wires are the res...
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energy momentum Cathodoluminescence spectroscopy of dielectric nanostructures
ACS Photonics, 2018Co-Authors: Sandro Mignuzzi, Toon Coenen, Monica Mota, Andrei P Mihai, Peter K Petrov, Rupert F Oulton, Stefan A Maier, Riccardo SapienzaAbstract:Precise knowledge of the local density of optical states (LDOS) is fundamental to understanding nanophotonic systems and devices. Complete LDOS mapping requires resolution in energy, momentum, and space, and hence a versatile measurement approach capable of providing simultaneous access to the LDOS components is highly desirable. Here, we explore a modality of Cathodoluminescence spectroscopy able to resolve, in single acquisitions, the dispersion in energy and momentum of the radiative LDOS. We perform measurements on a titanium nitride diffraction grating, bulk molybdenum disulfide, and silicon to demonstrate that the technique can probe and disentangle the dispersion of coherent and incoherent Cathodoluminescence signals. The approach presented raises Cathodoluminescence spectroscopy to a versatile tool for subwavelength design and optimization of nanophotonic devices in the reciprocal space.
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angle resolved Cathodoluminescence imaging polarimetry
ACS Photonics, 2016Co-Authors: Clara I Osorio, Toon Coenen, Albert Polman, Benjamin J M Brenny, Femius A KoenderinkAbstract:Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the polarization was not fully determined. Here we demonstrate a technique to access the full polarization state of the Cathodoluminescence emission, that is the Stokes parameters as a function of the emission angle. Using this technique, we measure the emission of metallic bullseye nanostructures and show that the handedness of the structure as well as nanoscale changes in excitation position induce large changes in polarization ellipticity and helicity. Furthermore, by exploiting the ability of polarimetry to distinguish polarized from unpolarized light, we quantify the contributions of different types of coherent and incoherent radiation to the emission of a gold surface, silicon and gallium arsenide bulk semicondu...
Moungi G Bawendi - One of the best experts on this subject based on the ideXlab platform.
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Cathodoluminescence and photoluminescence of highly luminescent cdse zns quantum dot composites
Applied Physics Letters, 1997Co-Authors: J Rodriguezviejo, Klavs F Jensen, Hedi Mattoussi, J Michel, B O Dabbousi, Moungi G BawendiAbstract:We report room-temperature Cathodoluminescence and photoluminescence spectra originating from ZnS overcoated CdSe nanocrystals, 33 and 42 A in diameter, embedded in a ZnS matrix. The thin-film quantum dot composites were synthesized by electrospray organometallic chemical vapor deposition. Cathodoluminescence and photoluminescence are dominated by the sharp band-edge emission characteristic of the initial nanocrystals. The emission wavelength can be tuned in a broad window (470–650 nm) by varying the size of the dots. The Cathodoluminescence intensity depends on the crystallinity of the ZnS matrix and the voltage and current density applied.
J Rodriguezviejo - One of the best experts on this subject based on the ideXlab platform.
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Cathodoluminescence and photoluminescence of highly luminescent cdse zns quantum dot composites
Applied Physics Letters, 1997Co-Authors: J Rodriguezviejo, Klavs F Jensen, Hedi Mattoussi, J Michel, B O Dabbousi, Moungi G BawendiAbstract:We report room-temperature Cathodoluminescence and photoluminescence spectra originating from ZnS overcoated CdSe nanocrystals, 33 and 42 A in diameter, embedded in a ZnS matrix. The thin-film quantum dot composites were synthesized by electrospray organometallic chemical vapor deposition. Cathodoluminescence and photoluminescence are dominated by the sharp band-edge emission characteristic of the initial nanocrystals. The emission wavelength can be tuned in a broad window (470–650 nm) by varying the size of the dots. The Cathodoluminescence intensity depends on the crystallinity of the ZnS matrix and the voltage and current density applied.
Ernst Jan R Vesseur - One of the best experts on this subject based on the ideXlab platform.
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angle resolved Cathodoluminescence spectroscopy
Applied Physics Letters, 2011Co-Authors: Toon Coenen, Ernst Jan R Vesseur, A PolmanAbstract:We present a Cathodoluminescence spectroscopy technique which combines deep subwavelength excitation resolution with angle-resolved detection capabilities. The Cathodoluminescence emission is collected by a paraboloid mirror (effective NA = 0.96) and is projected onto a 2D CCD array. The azimuthal and polar emission pattern is directly deduced from the image. As proof of principle, we use the technique to measure the angular distribution of transition radiation from a single crystalline gold surface under 30 keV electron irradiation. We find that the experiment matches very well with theory, illustrating the potential of this technique for the characterization of photonic structures with deep subwavelength dimensions.
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angle resolved Cathodoluminescence spectroscopy
arXiv: Mesoscale and Nanoscale Physics, 2011Co-Authors: Toon Coenen, Ernst Jan R Vesseur, A PolmanAbstract:We present a novel Cathodoluminescence spectroscopy technique which combines a deep subwavelength excitation resolution with angle-resolved detection capabilities. The Cathodoluminescence emission is collected by a paraboloid mirror (effective NA=0.96) and is projected onto a 2D CCD array. The azimuthal and polar emission pattern is directly deduced from the image. As proof of principle we use the technique to measure the angular distribution of transition radiation from a single crystalline gold surface under 30 keV electron irradiation. We find that the experiment matches very well with theory, illustrating the potential of this new technique for the characterization of photonic structures with deep subwavelength dimensions.
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plasmonic modes of annular nanoresonators imaged by spectrally resolved Cathodoluminescence
Nano Letters, 2007Co-Authors: Carrie E Hofmann, A Polman, Javier Garcia F De Abajo, Ernst Jan R Vesseur, Luke A Sweatlock, Henri J Lezec, Harry A. AtwaterAbstract:We report the observation of plasmonic modes of annular resonators in nanofabricated Ag and Au surfaces that are imaged by spectrally resolved Cathodoluminescence. A highly focused 30 keV electron beam is used to excite localized surface plasmons that couple to collective resonant modes of the nanoresonators. We demonstrate unprecedented resolution of plasmonic mode excitation and by combining these observations with full-field simulations find that Cathodoluminescence in plasmonic nanostructures is most efficiently excited at positions corresponding to antinodes in the modal electric field intensity.