| 1. |
- Ayyer, Kartik, et al.
(författare)
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3D diffractive imaging of nanoparticle ensembles using an x-ray laser
- 2021
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 8:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Single particle imaging at x-ray free electron lasers (XFELs) has the potential to determine the structure and dynamics of single biomolecules at room temperature. Two major hurdles have prevented this potential from being reached, namely, the collection of sufficient high-quality diffraction patterns and robust computational purification to overcome structural heterogeneity. We report the breaking of both of these barriers using gold nanoparticle test samples, recording around 10 million diffraction patterns at the European XFEL and structurally and orientationally sorting the patterns to obtain better than 3-nm-resolution 3D reconstructions for each of four samples. With these new developments, integrating advancements in x-ray sources, fast-framing detectors, efficient sample delivery, and data analysis algorithms, we illuminate the path towards sub-nano meter biomolecular imaging. The methods developed here can also be extended to characterize ensembles that are inherently diverse to obtain their full structural landscape. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.
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| 2. |
- 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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| 3. |
- 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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| 4. |
- Bergues, B., et al.
(författare)
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Tabletop nonlinear optics in the 100-eV spectral region
- 2018
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 5:3, s. 237-242
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Tidskriftsartikel (refereegranskat)abstract
- Nonlinear light-matter interactions in the extreme ultraviolet (XUV) are a prerequisite to perform XUV-pump/XUV-probe spectroscopy of core electrons. Such interactions are now routinely investigated at free-electron laser (FEL) facilities. Yet, electron dynamics are often too fast to be captured with the femtosecond resolution of state-of-the-art FELs. Attosecond pulses from laser-driven XUV-sources offer the necessary temporal resolution. However, intense attosecond pulses supporting nonlinear processes have only been available for photon energy below 50 eV, precluding XUV-pump/XUV-probe investigation of typical inner-shell processes. Here, we surpass this limitation by demonstrating two-photon absorption from inner electronic shells of xenon at photon energies around 93 eV and 115 eV. This advance opens the door for attosecond real-time observation of nonlinear electron dynamics deep inside atoms.
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| 5. |
- Bouchard, F., et al.
(författare)
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Quantum metrology at the limit with extremal Majorana constellations
- 2017
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 4:11, s. 1429-1432
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Tidskriftsartikel (refereegranskat)abstract
- Quantum metrology allows for a tremendous boost in the accuracy of measurement of diverse physical parameters. The estimation of a rotation constitutes a remarkable example of this quantum-enhanced precision. The recently introduced Kings of Quantumness are especially germane for this task when the rotation axis is unknown, as they have a sensitivity independent of that axis and they achieve a Heisenberg-limit scaling. Here, we report the experimental realization of these states by generating up to 21-dimensional orbital angular momentum states of single photons, and confirm their high metrological abilities.
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| 6. |
- Carine, J., et al.
(författare)
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Multi-core fiber integrated multi-port beam splitters for quantum information processing
- 2020
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Ingår i: Optica. - : OPTICAL SOC AMER. - 2334-2536. ; 7:5, s. 542-550
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Tidskriftsartikel (refereegranskat)abstract
- Multi-port beam splitters are cornerstone devices for high-dimensional quantum information tasks, which can outperform the two-dimensional ones. Nonetheless, the fabrication of such devices has proven to be challenging with progress only recently achieved with the advent of integrated photonics. Here, we report on the production of high-quality N x N (with N = 4, 7) multi-port beam splitters based on a new scheme for manipulating multi-core optical fibers. By exploring their compatibility with optical fiber components, we create four-dimensional quantum systems and implement the measurement-device-independent random number generation task with a programmable four-arm interferometer operating at a 2 MHz repetition rate. Due to the high visibilities observed, we surpass the one-bit limit of binary protocols and attain 1.23 bits of certified private randomness per experimental round. Our result demonstrates that fast switching, low loss, and high optical quality for high-dimensional quantum information can be simultaneously achieved with multi-core fiber technology. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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| 7. |
- Daurer, Benedikt J., et al.
(författare)
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Ptychographic wavefront characterization for single-particle imaging at x-ray lasers
- 2021
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 8:4, s. 551-562
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Tidskriftsartikel (refereegranskat)abstract
- A well-characterized wavefront is important for many x-ray free-electron laser (XFEL) experiments, especially for single-particle imaging (SPI), where individual biomolecules randomly sample a nanometer region of highly focused femtosecond pulses. We demonstrate high-resolution multiple-plane wavefront imaging of an ensemble of XFEL pulses, focused by Kirkpatrick–Baez mirrors, based on mixed-state ptychography, an approach letting us infer and reduce experimental sources of instability. From the recovered wavefront profiles, we show that while local photon fluence correction is crucial and possible for SPI, a small diversity of phase tilts likely has no impact. Our detailed characterization will aid interpretation of data from past and future SPI experiments and provides a basis for further improvements to experimental design and reconstruction algorithms.
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| 8. |
- de Beeck, Camiel Op, et al.
(författare)
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III/V-on-lithium niobate amplifiers and lasers
- 2021
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Ingår i: Optica. - 2334-2536. ; 8:10, s. 1288-1289
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We demonstrate electrically pumped, heterogeneously integrated lasers on thin-film lithium niobate, featuring electro-optic wavelength tunability. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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| 9. |
- Du, Mengqi, et al.
(författare)
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High-resolution wavefront sensing and aberration analysis of multi-spectral extreme ultraviolet beams
- 2023
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Ingår i: Optica. - : Optica Publishing Group. - 2334-2536. ; 10:2, s. 255-263
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Tidskriftsartikel (refereegranskat)abstract
- Coherent multi-spectral extreme ultraviolet beams have great potential for providing high spatial and temporal resolution for microscopy and spectroscopy applications. But due to the limitations of short-wavelength optics and the broad bandwidth, it remains a challenge to perform quantitative, high-resolution beam characterization. Here we present a wavefront sensing solution based on multiplexed ptychography, with which we show spectrally resolved, high-resolution beam reconstructions. Furthermore, using these high-fidelity quantitative wavefront measurements, we investigate aberration transfer mechanisms in the high-harmonic-generation process, where we present and explain harmonic-order-dependent astigmatism inheritance from the fundamental wavefront. This ptychographic wavefront sensing concept thus enables detailed studies of the high-harmonic-generation process, such as spatiotemporal effects in attosecond pulse formation.
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| 10. |
- Etcheverry, Sebastián, et al.
(författare)
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Microsecond switching of plasmonic nanorods in an all-fiber optofluidic component
- 2017
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 4:8, s. 864-870
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Tidskriftsartikel (refereegranskat)abstract
- As information technologies move from electron-to photon-based systems, the need to rapidly modulate light is of paramount importance. Here, we study the evolution of the electric-field-induced alignment of gold nanorods suspended in organic solvents. The experiments were performed using an all-fiber optofluidic device, which enables convenient interaction of light, electric fields, and the nanorod suspension. We demonstrate microsecond nanorod switching times, three orders of magnitude faster than a traditional Freederickcz-based liquid crystal alignment mechanism. We find that the dynamics of the alignment agrees well with the Einstein-Smoluchowski relationship, allowing for the determination of the rotational diffusion coefficient and polarizability anisotropy of the nanorods as well as the effective length of the ligands capping the nanorods. The ability to dynamically control the optical properties of these plasmonic suspensions coupled with the point-to-point delivery of light from the fiber component, as demonstrated in this work, may enable novel ultrafast optical switches, filters, displays, and spatial light modulators.
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