Featured
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Solution-phase sample-averaged single-particle spectroscopy of quantum emitters with femtosecond resolution
Combining fluorescence correlation spectroscopy and ultrafast spectroscopy, the sample-averaged dynamics of defects are studied with single-particle sensitivity in two-dimensional hexagonal boron nitride heterogeneous emitters.
- Jiaojian Shi
- , Yuejun Shen
- & Aaron M. Lindenberg
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News & Views |
“The unreasonable effectiveness of mathematics” in evading polaritonic losses
Polaritonic losses, a root impediment to the many bounties of nanophotonics, may be evaded by resorting to the mathematics of synthetic frequencies offering ‘virtual’ gain.
- Dmitri N. Basov
- & Michael M. Fogler
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Light-induced electronic polarization in antiferromagnetic Cr2O3
A light-induced polar electronic state is generated in Cr2O3; the symmetry reduction occurs on an ultrafast timescale, ruling out contributions from the lattice or spins.
- Xinshu Zhang
- , Tyler Carbin
- & Anshul Kogar
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Phase patterning of liquid crystal elastomers by laser-induced dynamic crosslinking
Lack of local phase patterning in liquid crystal elastomers has hindered their broad implementation. The authors report a laser-induced dynamic crosslinking approach with allyl sulfide groups to achieve reconfigurable high-resolution patterning of multiple liquid crystalline phases in a single film.
- Seok Hwan Choi
- , Ju Hee Kim
- & Seung Hwan Ko
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News & Views |
A thicker skin for better immune evasion
Cancer cells adjust the composition of their glycocalyx to increase its thickness and create a physical barrier that shields them from immune recognition and engagement.
- Edward N. Schmidt
- & Matthew S. Macauley
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| Open AccessParity–time-symmetric photonic topological insulator
The authors propose a non-Hermitian topological insulator with a real-valued energy spectrum based on a periodically driven Floquet model implemented in a photonic platform where generalized parity–time symmetry is protected against spontaneous symmetry breaking under a spatiotemporal gain and loss distribution.
- Alexander Fritzsche
- , Tobias Biesenthal
- & Alexander Szameit
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Compensating losses in polariton propagation with synthesized complex frequency excitation
Propagation losses have limited the practical use of polaritons in photonic applications. Here the authors demonstrate a substantial enhancement in the propagation distance of phonon polaritons, employing synthetic optical excitation of complex frequency with virtual gain synthesized by combining multiple real frequency measurements.
- Fuxin Guan
- , Xiangdong Guo
- & Shuang Zhang
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All-optical multilevel physical unclonable functions
Employing light-transformable polymers, multiple physical unclonable functions are demonstrated within a single device with all-optical reversible reconfigurability. Such devices may enable quantum secure authentication and nonlinear cryptographic key generation applications.
- Sara Nocentini
- , Ulrich Rührmair
- & Francesco Riboli
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Research Briefing |
Vibrational optical control via cation motions in perovskite solar cells
Hybrid organic–inorganic perovskite materials have promise as the photovoltaic technology of the future. A method for spectroscopic optical control reveals how the structural dynamics and vibrations of a perovskite’s organic cations affect the electronic performance of working photovoltaic devices.
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News & Views |
Quadrupolar excitons take the stage
Hybridized electron or hole states across semiconducting van der Waals monolayers in heterotrilayer systems enable the emergence of quadrupolar excitons. Quadrupolar excitons, unlike their dipolar counterparts, have a tunable static dipole moment that responds nonlinearly under an applied electric field.
- Elyse Barré
- , Medha Dandu
- & Archana Raja
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| Open AccessUltrafast vibrational control of organohalide perovskite optoelectronic devices using vibrationally promoted electronic resonance
Optically stimulated vibrational control for materials has the potential to improve the performance of optoelectronic devices. The vibrational control of FAPbBr3 perovskite solar cells has been demonstrated, where the fast dynamics of coupling between cations and inorganic sublattice may suppress non-radiative recombinations in perovskites, leading to reduced voltage losses.
- Nathaniel. P. Gallop
- , Dmitry R. Maslennikov
- & Artem A. Bakulin
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Compact angle-resolved metasurface spectrometer
Employing a miniaturized spectrometer that combines a metasurface-based spectrometer array and a metalens, angle-resolved spectral imaging is achieved with a wavelength accuracy of 0.17 nm, spectral resolution of 0.40 nm and angular resolution of 4.88 × 10−3 rad for a spectrometer with a 4 × 4 μm2 footprint.
- Guiyi Cai
- , Yanhao Li
- & Qinghai Song
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Observation of quadrupolar and dipolar excitons in a semiconductor heterotrilayer
The authors report the emergence of quadrupolar excitons in angle-aligned WSe2/WS2/WSe2 heterotrilayers characterized by a delocalized hole residing in both outer WSe2 layers, electric-field tunability and reduced exciton–exciton interactions.
- Leo Yu
- , Kateryna Pistunova
- & Tony F. Heinz
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News & Views |
Designer quantum dot molecules and beyond
Quantum dots couple to form artificial molecules that allow for variable colour emission in response to an electric field.
- James Cassidy
- , Justin Ondry
- & Dmitri V. Talapin
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Research Briefing |
A spin-optical monolayer laser based on a photonic spin lattice
Inspired by valley pseudospins in two-dimensional materials, high-quality-factor (high-Q) spin–valley states were created through the photonic Rashba-type spin splitting of a bound state in the continuum. This approach enabled the construction of a coherent and controllable spin-optical laser using monolayer-integrated spin–valley microcavities without requiring magnetic fields or cryogenic temperatures.
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Research Briefing |
Large-bandgap organic semiconductors with trap-free charge transport
By optimizing the molecular organization of blue-emitting organic semiconductors, the vulnerability of the materials to extrinsic impurities that cause charge trapping, such as oxygen and water, is strongly reduced. Steric shielding of the electron-transporting core is shown to increase the electron transport by several orders of magnitude.
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Broadband mid-infrared non-reciprocal absorption using magnetized gradient epsilon-near-zero thin films
Using doped InAs multilayers under moderate external magnetic fields with gradient epsilon-near-zero frequencies, broadband non-reciprocal absorption that can be tailored within the mid-infrared spectral region has been demonstrated.
- Mengqi Liu
- , Shuang Xia
- & Cheng-Wei Qiu
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Electric-field-induced colour switching in colloidal quantum dot molecules at room temperature
Current quantum dot emitters are limited to small-spectral-range colour tuning accompanied by intensity reduction. Electric-field-induced reversible emission colour switching without intensity loss can be achieved on a single-particle level in quantum dot molecules with two coupled emission centres.
- Yonatan Ossia
- , Adar Levi
- & Uri Banin
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News & Views |
A new spin on impact ionization
Quantum dots are engineered to use dopant states to achieve substantially enhanced impact ionization, which is potentially useful for light-harvesting applications.
- Miri Kazes
- & Dan Oron
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Article
| Open AccessSpin-exchange carrier multiplication in manganese-doped colloidal quantum dots
Carrier multiplication generates multiple excitons for each absorbed photon but is normally limited by fast phonon-assisted relaxation. Here the authors achieve a threefold enhancement in multiexciton yields in Mn-doped PbSe/CdSe quantum dots, due to very fast spin-exchange interactions between Mn ions and the quantum dots that outpace energy losses arising from phonon emission.
- Ho Jin
- , Clément Livache
- & Victor I. Klimov
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Spin-valley Rashba monolayer laser
The authors introduce a spin-optical laser based on a monolayer transition metal dichalcogenide coupled to a heterostructure microcavity supporting high-Q spin-valley resonances originating from photonic Rashba-type spin splitting of a bound state in the continuum.
- Kexiu Rong
- , Xiaoyang Duan
- & Erez Hasman
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Research Briefing |
A strategy for obtaining AlN heteroepitaxial films with high crystalline quality
High-quality aluminium nitride (AlN) heteroepitaxial films are obtained by the controlled discretization and coalescence of columns using nanopatterned AlN/sapphire templates with regular hexagonal holes. The density of dislocation etch pits in the AlN heteroepitaxial films is reduced to approximately 104 cm–2, approaching the value of that in AlN bulk single crystals.
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Research Briefing |
Scalar photonic crystals with non-radiative topological surface modes
A scalar scheme has been proposed to design photonic crystals that possess bulk dispersions resembling scalar waves and surface modes that support skyrmion-like textures. This approach addresses the challenges of realizing three-dimensional topological photonic crystals, which usually have complicated dispersions and leaky surface modes inside the light cone.
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Scalar topological photonic nested meta-crystals and skyrmion surface states in the light cone continuum
Employing connected coaxial waveguides on a nested meta-crystal configuration, the authors design photonic crystals with scalar-wave-like band dispersions, facilitating the search for topological phases in three-dimensional photonic crystals.
- Biao Yang
- , Qinghua Guo
- & C. T. Chan
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Multiple and spectrally robust photonic magic angles in reconfigurable α-MoO3 trilayers
The direction of polariton canalization—its diffractionless propagation—in twisted bilayers at the magic angle is hindered by the lack of multiple magic angles. By controlling the twist angles between three α-MoO3 layers, reconfigurable and spectrally robust polariton canalization along any in-plane direction is demonstrated.
- J. Duan
- , G. Álvarez-Pérez
- & P. Alonso-González
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| Open AccessIntrinsic strong light-matter coupling with self-hybridized bound states in the continuum in van der Waals metasurfaces
The authors demonstrate strong coupling in bound state in the continuum metasurfaces on nanostructured bulk WS2 and exhibiting sharp resonances with tailored linewidths and controllable light-matter coupling strength.
- Thomas Weber
- , Lucca Kühner
- & Andreas Tittl
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News & Views |
Ultrafast push for counterintuitive spintronics
Current-inducing switching of magnetization is crucial for future magnetic data processing technologies, but switching it with speed and energy efficiency remains challenging. Using femtosecond optical pulses, instead of conventional charge currents, is found to make spintronics not only ultrafast but also counterintuitive.
- Dmytro Afanasiev
- & Alexey V. Kimel
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News & Views |
Writing above the bandgap
Above-bandgap, nanosecond laser pulses enable the localized in situ writing of spin defects in prefabricated nanophotonic cavities. The approach preserves defect and cavity mode properties, key requirements towards cavity–emitter coupling in quantum networks.
- Sridhar Majety
- & Marina Radulaski
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Strongly enhanced light–matter coupling of monolayer WS2 from a bound state in the continuum
Combining a tungsten disulfide monolayer and a topologically protected bound state in the continuum formed by a one-dimensional photonic crystal, strong light–matter interaction enhancement and large exciton–polariton nonlinearities at room temperature are demonstrated.
- Eugenio Maggiolini
- , Laura Polimeno
- & Dario Ballarini
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Letter
| Open AccessPicophotonic localization metrology beyond thermal fluctuations
The authors report subatomic precision in measuring the displacement of a nanowire. Such precision is achieved by employing deep-learning enabled analysis of single-shot scattering of topologically structured superoscillatory illumination.
- Tongjun Liu
- , Cheng-Hung Chi
- & Nikolay I. Zheludev
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Real-space observation of ultraconfined in-plane anisotropic acoustic terahertz plasmon polaritons
Employing terahertz nanoscopy, we image highly confined, in-plane anisotropic acoustic terahertz plasmon polaritons in monoclinic Ag2Te platelets placed above a Au layer, verifying a linear dispersion and elliptical isofrequency contour in momentum space.
- S. Chen
- , P. L. Leng
- & R. Hillenbrand
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Laser writing of spin defects in nanophotonic cavities
Using direct laser writing with a nanosecond pulsed laser operating at above-bandgap photon energies, we demonstrate the selective formation of spin defects in photonic crystal cavities in 4H-silicon carbide and their in situ characterization.
- Aaron M. Day
- , Jonathan R. Dietz
- & Evelyn L. Hu
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Letter |
Compact spin-valley-locked perovskite emission
We report compact spin-valley-locked perovskite emitting metasurfaces where spin-dependent geometric phases are imparted into bound states in the continuum via Brillouin zone folding, simultaneously enabling chiral purity, directionality and large emission angles.
- Yang Chen
- , Jiangang Feng
- & Cheng-Wei Qiu
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Layer-dependent correlated phases in WSe2/MoS2 moiré superlattice
The authors demonstrate electrical on/off switching of interlayer interactions in tungsten diselenide/molybdenum disulfide heterobilayers, the phase diagram of which contains layer-dependent correlated regions that reveal the role of strong correlations in interlayer exciton dynamics.
- Qinghai Tan
- , Abdullah Rasmita
- & Weibo Gao
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High-efficiency stretchable light-emitting polymers from thermally activated delayed fluorescence
We synthesized stretchable electroluminescent polymers capable of reaching a near-unity theoretical quantum yield through thermally activated delayed fluorescence. Their polymers show 125% stretchability with 10% external quantum efficiency and demonstrate a fully stretchable organic light-emitting diode.
- Wei Liu
- , Cheng Zhang
- & Sihong Wang
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Ambipolar charge-transfer graphene plasmonic cavities
Employing an oxidation-activated charge transfer strategy to oxidize transition-metal dichalcogenides into transition-metal oxides, the authors imprint plasmonic cavities with laterally abrupt doping profiles and nanoscale precision demonstrating plasmonic whispering-gallery resonators.
- Brian S. Y. Kim
- , Aaron J. Sternbach
- & D. N. Basov
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Optically induced ultrafast magnetization switching in ferromagnetic spin valves
The authors demonstrate optically induced ultrafast magnetization reversal taking place within less than a picosecond in rare-earth-free spin valves of [Pt/Co]/Cu/[Co/Pt].
- Junta Igarashi
- , Wei Zhang
- & Grégory Malinowski
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News & Views |
See how they run
Time-dependent pump–probe studies of polaritonic transport — for polaritons formed by strong coupling between organic molecules and Bloch surface waves at the interface of a distributed Bragg reflector — reveal a transition between diffusive and ballistic behaviour.
- Jonathan Keeling
- & Graham Turnbull
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Chiral-phonon-activated spin Seebeck effect
The authors report spin current generation in a metallic layer adjacent to a non-magnetic chiral hybrid organic–inorganic perovskite when subjected to a thermal gradient, and attribute this to chiral phonons possessing angular momentum.
- Kyunghoon Kim
- , Eric Vetter
- & Jun Liu
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Tunable photon-induced spatial modulation of free electrons
On-demand electron wavefront shaping is desirable for applications from nanolithography to imaging. Here, the authors present tunable photon-induced spatial modulation of electrons through their interaction with externally controlled surface plasmon polaritons.
- Shai Tsesses
- , Raphael Dahan
- & Ido Kaminer
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From enhanced diffusion to ultrafast ballistic motion of hybrid light–matter excitations
The authors study ultrafast spatiotemporal dynamics of polaritons formed by mixing surface-bound optical waves with excitons observing a mobility transition from diffusive to ballistic transport flow at two-thirds the speed of light.
- Mukundakumar Balasubrahmaniyam
- , Arie Simkhovich
- & Tal Schwartz
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Topological steering of light by nematic vortices and analogy to cosmic strings
Liquid crystal (LC) applications typically rely on defining the non-topological spatial patterns of the optical axis. Here, the authors demonstrate the topological steering of light by LC nematic vortices, futher establishing an analogy between topological light steering by LC vortices and cosmic strings.
- Cuiling Meng
- , Jin-Sheng Wu
- & Ivan I. Smalyukh
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| Open AccessExchange controlled triplet fusion in metal–organic frameworks
Triplet-fusion-based photon upconversion is promising for photovoltaic or bioimaging applications, but its efficiency is limited by triplet fusion spin dependence. Here, the authors tailor spin dynamics by engineering the crystal structure with metal–organic frameworks to enable effective spin mixing between singlet and quintet triplet–triplet pair states.
- Dong-Gwang Ha
- , Ruomeng Wan
- & Mircea Dincă
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All-optical switching of magnetization in atomically thin CrI3
The authors use circularly polarized light pulses to trigger all-optical magnetization switching in an atomically thin ferromagnetic semiconductor. The switching process is related to spin angular momentum transfer from photoexcited carriers to local magnetic moments.
- Peiyao Zhang
- , Ting-Fung Chung
- & Xiang Zhang
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News & Views |
Locking exciton fine-structure splitting
Ensemble-level experimental evidence of exciton fine-structure splitting in perovskite quantum dots has been demonstrated, correlated to the intrinsic symmetry of these nanocrystals.
- Gabriele Rainò
- & Maksym V. Kovalenko
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Lattice distortion inducing exciton splitting and coherent quantum beating in CsPbI3 perovskite quantum dots
Halide perovskites feature highly dynamic lattices, but their impact on exciton fine structure remains unexplored. Here, the authors show that these lattices lead to a bright-exciton fine structure gap, enabling observation of quantum beats in a non-uniform ensemble.
- Yaoyao Han
- , Wenfei Liang
- & Kaifeng Wu
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News & Views |
Ultrafast light-based logic with graphene
By exploiting subfemtosecond control of light pulses, researchers demonstrate an ultrafast logic gate based on the waveform-dependent photocurrent generated by real and virtual carriers in graphene.
- Klaas-Jan Tielrooij
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Comment |
The revolution of silicon photonics
The success of silicon photonics is a product of two decades of innovations. This photonic platform is enabling novel research fields and novel applications ranging from remote sensing to ultrahigh-bandwidth communications. The future of silicon photonics depends on our ability to ensure scalability in bandwidth, size and power.
- Michal Lipson