Suchergebnisse

Plasmonic excitations, such as surface-plasmonpolaritons (SPPs) and graphene-plasmons (GPs), carry large momenta and are thus able to confine electromagnetic fields to small dimensions. This property makes them ideal platforms for subwavelength optical control and manipulation at the nanoscale. The momenta of these plasmons are even further increased if a scheme of metal-insulator-metal and graphene-insulator-metal are used for SPPs and GPs, respectively. However, with such large momenta, their far-field excitation becomes challenging. In this work, we consider hybrids of graphene and metallic nanostructures and study the physical mechanisms behind the interaction of far-field light with the supported high momenta plasmon modes. While there are some similarities in the properties of GPs and SPPs, since both are of the plasmon-polariton type, their physical properties are also distinctly different. For GPs we find two different physical mechanism related to either GPs confined to isolated cavities or large area collective grating couplers. Strikingly, we find that, although the two systems are conceptually different, under specific conditions, they can behave similarly. By applying the same study to SPPs, we find a different physical behavior, which fundamentally stems from the different dispersion relations of SPPs as compared to GPs. Furthermore, these hybrids produce large field enhancements that can also be electrically tuned and modulated making them the ideal candidates for a variety of plasmonic devices. ; N.M.R. P. and F. H.L.K. acknowledge support from the European Commission through the Project "Graphene-Driven Revolutions in ICT and Beyond" (Ref. No. 881603, CORE 3). N. M.R. P. and T.G.R. acknowledge COMPETE 2020, PORTUGAL 2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) through Project POCI-01-0145-FEDER-028114. F.H.L.K. acknowledges financial support from the Government of Catalonia through the SGR Grant, and from the Spanish Ministry of Economy and Competitiveness through ...

Graphene hybrids, made of thin insulators, graphene, and metals can support propagating acoustic plasmons (AGPs). The metal screening modifies the dispersion relation of usual graphene plasmons leading to slowly propagating plasmons, with record confinement of electromagnetic radiation. Here, we show that a graphene monolayer, covered by a thin dielectric material and an array of metallic nanorods, can be used as a robust platform to emulate the Su-Schrieffer-Heeger model. We calculate the Zak's phase of the different plasmonic bands to characterize their topology. The system shows bulk-edge correspondence: strongly localized interface states are generated in the domain walls separating arrays in different topological phases. We find signatures of the nontrivial phase which can directly be probed by far-field mid-IR radiation, hence allowing a direct experimental confirmation of graphene topological plasmons. The robust field enhancement, highly localized nature of the interface states, and their gate-tuned frequencies expand the capabilities of AGP-based devices. ; T.G.R. acknowledges funding from Fundacao para a Ciência e a Tecnologia and Instituto de Telecomunicacoes. grant number UID/50008/2020.in the framework of the project Sym-Break and Mario G. Silveirinha for useful discussions. Y.V.B., N.M.R.P. and F.H.L.K. acknowledge support from the European Commission through the project "Graphene-Driven Revolutions in ICT and Beyond" (ref. no. 881603, CORE 3). Y.V.B. and N.M.R.P. acknowledge COMPETE 2020, PORTUGAL 2020, FEDER, and the Portuguese Foundation for Science and Technology (FCT) through project POCI-010145-FEDER-028114. F.H.L.K. acknowledges financial support from the Government of Catalonia through the SGR grant, the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in RD (SEV-2015-0522), Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, the Mineco grants Ramon y Cajal (RYC-201212281), Plan Nacional ...

et al. ; Optoelectronic devices utilizing graphene have demonstrated unique capabilities and performances beyond state-of-the-art technologies. However, requirements in terms of device quality and uniformity are demanding. A major roadblock towards high-performance devices are nanoscale variations of the graphene device properties, impacting their macroscopic behaviour. Here we present and apply non-invasive optoelectronic nanoscopy to measure the optical and electronic properties of graphene devices locally. This is achieved by combining scanning near-field infrared nanoscopy with electrical read-out, allowing infrared photocurrent mapping at length scales of tens of nanometres. Using this technique, we study the impact of edges and grain boundaries on the spatial carrier density profiles and local thermoelectric properties. Moreover, we show that the technique can readily be applied to encapsulated graphene devices. We observe charge build-up near the edges and demonstrate a solution to this issue. ; F.H.L.K. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the 'Severo Ochoa' Programme for Centres of Excellence in R&D (SEV-2015-0522), support by Fundacio Cellex Barcelona, the ERC Career integration grant (294056, GRANOP), the ERC starting grant (307806, CarbonLight), the Government of Catalonia trough the SGR grant (2014-SGR-1535), the Mineco grants Ramón y Cajal (RYC-2012-12281) and Plan Nacional (FIS2013-47161-P), and project GRASP (FP7-ICT-2013-613024-GRASP). F.H.L.K. and R.H. acknowledge support by the E.C. (European Commission) under Graphene Flagship (contract no. CNECT-ICT604391). D.J. acknowledges support from the Ramón y Cajal Fellowship Program. Y.G. and J.H. acknowledge support from the US Office of Naval Research N00014-13-1-0662. We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness and 'Fondo Europeo de Desarrollo Regional' through Grant TEC2013-46168-R. Q.M. and P.J.-H. have been supported by AFOSR Grant No. FA9550-11-1-0225 and the Packard Fellowship program. This work made use of the Materials Research Science and Engineering Center Shared Experimental Facilities supported by the National Science Foundation (NSF) (Grant No. DMR-0819762) and of Harvard's Center for Nanoscale Systems, supported by the NSF (Grant No. ECS-0335765). S.R. acknowledges the Spanish Ministry of Economy and Competitiveness for funding (MAT2012-33911), the Secretaria de Universidades e Investigacion del Departamento de Economia y Conocimiento de la Generalidad de Catalunya and the Severo Ochoa Program (MINECO SEV-2013-0295). J.E.B.-V. acknowledges support from SECITI (Mexico, D.F.). ; Peer Reviewed

2D materials support unique excitations of quasi-particles that consist of a material excitation and photons called polaritons. Especially interesting are in-plane propagating polaritons, which can be confined to a single monolayer and carry large momentum. In this work, we theoretically predict the existence of a new type of in-plane propagating polariton, supported on monolayer transition-metal-dicalcogonides (TMDs) in the visible spectrum. This 2D in-plane exciton-polariton (2DEP) is described by the coupling of an electromagnetic light field with the collective oscillations of the excitons supported by monolayer TMDs. We experimentally demonstrate the specific conditions required for the excitation of the 2DEP and show that these can be achieved if the TMD is encapsulated with hexagonal-boron-nitride (hBN) and cooled to cryogenic temperatures. In addition, we compare the properties of the 2DEP with those of the surface-plasmon-polariton at the same spectral range, and find that the 2DEP exhibit over two orders-of-magnitude larger wavelength confinement. Finally, we propose and numerically demonstrate two configurations for the possible experimental observation of 2DEPs. ; - I E thanks Dr Fabien Vialla. J H and D R acknowledge the funding support by the NSF MRSEC program through Columbia in the Center for Precision Assembly of Superstratic and Superatomic Solids (DMR-1420634). H G and B F acknowledge support from ERC advanced grant COMPLEXPLAS. F H L K acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV-2015-0522), support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the Mineco grants Plan Nacional (FIS2016-81044-P) and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreement no.785219 ...

Conducting materials typically exhibit either diffusive or ballistic charge transport. When electron–electron interactions dominate, a hydrodynamic regime with viscous charge flow emerges. More stringent conditions eventually yield a quantum-critical Dirac-fluid regime, where electronic heat can flow more efficiently than charge. However, observing and controlling the flow of electronic heat in the hydrodynamic regime at room temperature has so far remained elusive. Here we observe heat transport in graphene in the diffusive and hydrodynamic regimes, and report a controllable transition to the Dirac-fluid regime at room temperature, using carrier temperature and carrier density as control knobs. We introduce the technique of spatiotemporal thermoelectric microscopy with femtosecond temporal and nanometre spatial resolution, which allows for tracking electronic heat spreading. In the diffusive regime, we find a thermal diffusivity of roughly 2,000 cm s, consistent with charge transport. Moreover, within the hydrodynamic time window before momentum relaxation, we observe heat spreading corresponding to a giant diffusivity up to 70,000 cm s, indicative of a Dirac fluid. Our results offer the possibility of further exploration of these interesting physical phenomena and their potential applications in nanoscale thermal management. ; We thank M. Polini and P. Piskunow for fruitful discussions, and H. Agarwal and K. Soundarapandian for help with sample fabrication. We acknowledge the following funding sources: European Union's Horizon 2020 research and innovation programme under grant nos. 804349 (K.-J.T.), 873028 (A.P.), 785219 (F.H.L.K. and S.R.), 881603 (F.H.L.K. and S.R.) and 670949 (N.F.v.H.); Spanish MCIU/AEI under grant nos. RYC-2017-22330 (K.-J.T.), PID2019-111673GB-I00 (K.-J.T.), BES-2016-078727 (M.L.), RTI2018-099957-J-I00 (M.L.) and PGC2018-096875-B-I00 (M.L. and N.F.v.H.); the Government of Catalonia under grant nos. SGR1656 (F.H.L.K.) and 2017SGR1369 (N.F.v.H.) and the CERCA program (ICN2 and ICFO); Spanish MINECO under grant nos. SEV-2017-0706 (ICN2) and CEX-2019-000910-S (ICFO); the International PhD fellowship program 'la Caixa' (A.B.); Leverhulme Trust grant no. RPG-2019-363 (A.P.); the Elemental Strategy Initiative conducted by the MEXT, Japan, grant no. JPMXP0112101001 (K.W. and T.T.), JSPS KAKENHI grant no. JP20H00354 (K.W. and T.T.) and the CREST (grant no. JPMJCR15F3) and JST (K.W. and T.T.); Fundació Privada Cellex (ICFO) and Fundació Mir-Puig (ICFO).

Combining the quantum optical properties of single-photon emitters with the strong near-field interactions available in nanophotonic and plasmonic systems is a powerful way of creating quantum manipulation and metrological functionalities. The ability to actively and dynamically modulate emitter-environment interactions is of particular interest in this regard. While thermal, mechanical and optical modulation have been demonstrated, electrical modulation has remained an outstanding challenge. Here we realize fast, all-electrical modulation of the near-field interactions between a nanolayer of erbium emitters and graphene, by in-situ tuning the Fermi energy of graphene. We demonstrate strong interactions with a >1000-fold increased decay rate for ~25% of the emitters, and electrically modulate these interactions with frequencies up to 300 kHz – orders of magnitude faster than the emitter's radiative decay (~100 Hz). This constitutes an enabling platform for integrated quantum technologies, opening routes to quantum entanglement generation by collective plasmon emission or photon emission with controlled waveform. ; K.-J.T. acknowledges funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 804349. ICN2 was supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706). This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 712721 (NanOQTech). F.H.L.K. acknowledges financial support from the Government of Catalonia trough the SGR grant, and from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV-2015-0522), and Explora Ciencia FIS2017-91599-EXP. F.H.L.K. also acknowledges support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the Mineco grants Plan Nacional (FIS2016-81044-P) and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union's Horizon 2020 under Grant Agreements No. 785219 (Core2) and No. 881603 (Core3) Graphene Flagship, and No. 820378 (Quantum Flagship). This work was supported by the ERC TOPONANOP under Grant Agreement No. 726001. ; Peer reviewed

Atomic layer deposited (ALD) Y2O3 thin films have been thoroughly investigated for optical or electronic applications. The coherent spectroscopy of lanthanide ions doped into this material has also recently attracted increasing interest in the field of quantum technologies for which they are considered promising candidates in quantum memories or as spin-photon interfaces. However, these most demanding applications require a deep control over the local positioning of the ions and their close environment in the crystalline matrix. This study focuses on the structural as well as optical properties of Eu3+ and Er3+ dopants in Y2O3 using photoluminescence (PL), luminescence decay times, and inhomogeneous line width (Γinh) measurements within this particular context. While as-grown ALD films do not provide an ideal host for the emitters, we demonstrate that by optimizing the deposition conditions and using appropriate annealing post treatments narrow inhomogeneous lines can be obtained for the 7F0↔5D0 transition of Eu3+ even for nanoscale films. Furthermore, about 1.5 ms lifetime has been measured for the infrared telecom transition of Er in ultrathin films (<10 nm), which is an order of magnitude higher than in nanoparticles of the same size. These results validate optimized rare-earth-doped ALD Y2O3 films as a suitable platform for photonics applications where few-nanometer-thick films with well-localized emitters are mandatory. This approach provides the first building blocks toward the development of more complex devices for quantum sensing or hybrid structures coupled with other systems such as two-dimensional materials ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no 712721 (NanOQTech). We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV-2015-0522), support by Fundacio Cellex Barcelona and Generalitat de Catalunya through the CERCA programm. IC2N is supported by "Severo Ochoa" program from Spanish MINECO (SEV-2017-0706).

In this paper we analyze the effects of nonlocality on the optical properties of a system consisting of a thin metallic film separated from a graphene sheet by a hexagonal boron nitride (hBN) layer. We show that nonlocal effects in the metal have a strong impact on the spectrum of the surface plasmon-polaritons on graphene. If the graphene sheet is shaped into a grating, we show that the extinction curves can be used to shed light on the importance of nonlocal effects in metals. Therefore, graphene surface plasmons emerge as a tool for probing nonlocal effects in metallic nanostructures, including thin metallic films. As a byproduct of our study, we show that nonlocal effects lead to smaller losses for the graphene plasmons than what is predicted by a local calculation. We show that these effects can be very well mimicked using a local theory with an effective spacer thickness larger than its actual value. ; The authors thank Sébastien Nanot and Itai Epstein for valuable discussions and comments. E.J.C.D., Yu.V.B. and N.M.R.P. acknowledge support from the European Commission through the project GrapheneDriven Revolutions in ICT and Beyond (Ref. No. 785219), and from the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Financing UID/FIS/04650/2013. E.J.C.D. acknowledges FCT for the grant CFUM-BI-14/2016. D.A.I. acknowledges the FPI grant BES-2014-068504. F.H.L.K. acknowledges financial support from the Government of Catalonia trough the SGR grant (2014-SGR-1535), and from the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2015-0522), support by Fundacio Cellex Barcelona, CERCA Programme / Generalitat de Catalunya and the Mineco grants Ramn y Cajal (RYC-2012-12281) and Plan Nacional (FIS201347161-P and FIS2014-59639-JIN). Furthermore, the research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreement no.696656 Graphene Flagship, the ...

Due to its outstanding electrical properties and chemical stability, graphene finds widespread use in various electrochemical applications. Although the presence of electrolytes strongly affects its electrical conductivity, the underlying mechanism has remained elusive. Here, we employ terahertz spectroscopy as a contact-free means to investigate the impact of ubiquitous cations (Li+, Na+, K+, and Ca2+) in aqueous solution on the electronic properties of SiO2-supported graphene. We find that, without applying any external potential, cations can shift the Fermi energy of initially hole-doped graphene by ∼200 meV up to the Dirac point, thus counteracting the initial substrate-induced hole doping. Remarkably, the cation concentration and cation hydration complex size determine the kinetics and magnitude of this shift in the Fermi level. Combined with theoretical calculations, we show that the ion-induced Fermi level shift of graphene involves cationic permeation through graphene. The interfacial cations located between graphene and SiO2 electrostatically counteract the substrate-induced hole doping effect in graphene. These insights are crucial for graphene device processing and further developing graphene as an ion-sensing material. ; X.J., Z.L., Z.C., A.N., K.M., M.B., and H.I.W. acknowledge the financial support by the Max Planck Society. X.J. acknowledges support by a Deutsche Forschungsgemeinschaft-funded position through the Excellence Initiative by the Graduate School of Excellence Materials Science in Mainz (MAINZ) (GSC 266) and support from the Max Planck Graduate Center mit der Johannes Gutenberg-Universität Mainz (MPGC). K.-J.T. acknowledges financial support through the MAINZ Visiting Professorship. X.Y. acknowledges the fellowship support from Chinese Scholarship Council (CSC). This project has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 804349. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706). F.H.L.K. acknowledges financial support by Fundacio Cellex Barcelona, support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV-2015-0522), and support by the Generalitat de Catalunya through the CERCA program. ; Peer reviewed

Although the detection of light at terahertz (THz) frequencies is important for a large range of applications, current detectors typically have several disadvantages in terms of sensitivity, speed, operating temperature, and spectral range. Here, we use graphene as a photoactive material to overcome all of these limitations in one device. We introduce a novel detector for terahertz radiation that exploits the photothermoelectric (PTE) effect, based on a design that employs a dual-gated, dipolar antenna with a gap of ∼100 nm. This narrow-gap antenna simultaneously creates a pn junction in a graphene channel located above the antenna and strongly concentrates the incoming radiation at this pn junction, where the photoresponse is created. We demonstrate that this novel detector has an excellent sensitivity, with a noise-equivalent power of 80 pW/ at room temperature, a response time below 30 ns (setup-limited), a high dynamic range (linear power dependence over more than 3 orders of magnitude) and broadband operation (measured range 1.8–4.2 THz, antenna-limited), which fulfills a combination that is currently missing in the state-of-the-art detectors. Importantly, on the basis of the agreement we obtained between experiment, analytical model, and numerical simulations, we have reached a solid understanding of how the PTE effect gives rise to a THz-induced photoresponse, which is very valuable for further detector optimization. ; F.H.L.K. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Program for Centres of Excellence in R&D (SEV-2015-0522), support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union Seventh Framework Program under grant agreement no.785219 Graphene Flagship (Core2). ICN2 is supported by the Severo Ochoa program from Spanish MINECO (grant no. SEV-2017-0706). K.-J.T. acknowledges support from a Mineco Young Investigator Grant (FIS2014-59639-JIN). S.C. acknowledges funding from the Barcelona Institute of Science and Technology (BIST), the Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya and the European Social Fund, FEDER. M.S.V. acknowledges financial support from the ERC Project 681379 (SPRINT) and partial support from the second half of the Balzan Prize 2016 in applied photonics delivered to Federico Capasso. A.Y.N. acknowledges funding from the Spanish Ministry of Economy, Industry and Competitiveness, national project MAT2017-88358-C3-3-R. R.H. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through the project MDM-2016-0618 of the Maria de Maeztu Units of Excellence Programme. ; Peer reviewed

Acoustic graphene plasmons are highly confined electromagnetic modes carrying large momentum and low loss in the mid-infrared and terahertz spectra. However, until now they have been restricted to micrometer-scale areas, reducing their confinement potential by several orders of magnitude. Using a graphene-based magnetic resonator, we realized single, nanometer-scale acoustic graphene plasmon cavities, reaching mode volume confinement factors of ~5 × 1010 Such a cavity acts as a mid-infrared nanoantenna, which is efficiently excited from the far field and is electrically tunable over an extremely large broadband spectrum. Our approach provides a platform for studying ultrastrong-coupling phenomena, such as chemical manipulation via vibrational strong coupling, as well as a path to efficient detectors and sensors operating in this long-wavelength spectral range. ; I.E. would like to thank Eduardo J. C. Dias for fruitful discussions and Dr. Fabien Vialla. D.R.S acknowledges the support of AFOSR(FA9550-12-1-0491, FA9550-18-1-0187) grants. N.M.R.P. acknowledges support from the European Commission through the project "Graphene-Driven Revolutions in ICT and Beyond" (Ref. use CORE 3 reference, not CORE 2). N.M.R.P. and T.G.R. acknowledge COMPETE 2020, PORTUGAL 2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) through project POCI-01- 0145-FEDER-028114. F.H.L.K. acknowledges financial support from the Government of Catalonia trough the SGR grant, and from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R and D (SEV-2015- 0522), support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the Mineco grants Ramón y Cajal (RYC-2012-12281, Plan Nacional (FIS2013-47161-P and FIS2014-59639-JIN) and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union Seventh Framework ...

Integrating and manipulating the nano-optoelectronic properties of Van der Waals heterostructures can enable unprecedented platforms for photodetection and sensing. The main challenge of infrared photodetectors is to funnel the light into a small nanoscale active area and efficiently convert it into an electrical signal. Here, we overcome all of those challenges in one device, by efficient coupling of a plasmonic antenna to hyperbolic phonon-polaritons in hexagonal-BN to highly concentrate mid-infrared light into a graphene pn-junction. We balance the interplay of the absorption, electrical and thermal conductivity of graphene via the device geometry. This approach yields remarkable device performance featuring room temperature high sensitivity (NEP of 82 pW/Hz−−−√) and fast rise time of 17 nanoseconds (setup-limited), among others, hence achieving a combination currently not present in the state-of-the-art graphene and commercial mid-infrared detectors. We also develop a multiphysics model that shows very good quantitative agreement with our experimental results and reveals the different contributions to our photoresponse, thus paving the way for further improvement of these types of photodetectors even beyond mid-infrared range. ; F.H.L.K. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R& D (SEV-2015-0522), support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreement no. 785219 and no. 881603 Graphene Flagship for Core2 and Core3. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706). K.J.T. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 804349. R.H. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (national project RTI2018-094830-B-100 and the project MDM-2016-0618 of the Marie de Maeztu Units of Excellence Program) and the Basque Government (grant No. IT1164-19). S.C. acknowledges financial support from the Barcelona Institute of Science and Technology (BIST), the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya and the European Social Fund (L'FSE inverteix en el teu futur)—FEDER. D.E. acknowledges partial support from the Army Research Office MURI "Ab-Initio Solid-State Quantum Materials" Grant No. W911NF18-1-0431. J.G. was supported by the ARL-MIT Institute for Soldier Nanotechnologies (ISN). T.S. and L.M.M. acknowledge support by Spain's MINECO under Grant No. MAT2017-88358-C3-1-R and the Aragon Government through project Q-MAD. ; Peer reviewed

Solid-state single photon sources (SPSs) with narrow line width play an important role in many leading quantum technologies. Within the wide range of SPSs studied to date, single fluorescent molecules hosted in organic crystals stand out as bright, photostable SPSs with a lifetime-limited optical resonance at cryogenic temperatures. Furthermore, recent results have demonstrated that photostability and narrow line widths are still observed from single molecules hosted in a nanocrystalline environment, which paves the way for their integration with photonic circuitry. Polymers offer a compatible matrix for embedding nanocrystals and provide a versatile yet low-cost approach for making nanophotonic structures on chip that guide light and enhance coupling to nanoscale emitters. Here, we present a deterministic nanostructuring technique based on electron-beam lithography for shaping polymers with embedded single molecules. Our approach provides a direct means of structuring the nanoscale environment of narrow line width emitters while preserving their emission properties. ; We would like to thank Josep Canet Ferrer and Vittoria Finazzi. This project has received funding from the EraNET Cofund Initiatives QuantERA under the European Union's Horizon 2020 research and innovation programme grant agreement No. 731473 (Project acronyme: ORQUID). C.C. acknowledges financial support by the ICFOstepstone - PhD Programme for Early-Stage Researchers in Photonics, funded by the Marie Skłodowska-Curie Co-funding of regional, national, and international programmes (GA665884) of the European Commission. C.D. acknowledges financial support by the European Union's Horizon 2020 research and innovation programme (ERC Grant No. StG637116). A.L. and E.B. acknowledge "Ente cassa di risparmio di Firenze" for financial support given for the acquisition of the TESCAN GAIA3 electron microscope , and Regione Toscana for the project FELIX (POR FESR 2014-2020, grant number no. 6455). We also acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO), through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV-2015-0522 and SEV-2015-0496), support by Fundaciò Cellex Barcelona, Generalitat de Catalunya through the CERCA program. This work received funding from the European Union's Horizon 2020 research and innovation program Quantum Flagship (Grant No. 820378). Funded by the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. ; Peer reviewed

Integrating and manipulating the nano-optoelectronic properties of Van der Waals heterostructures can enable unprecedented platforms for photodetection and sensing. The main challenge of infrared photodetectors is to funnel the light into a small nanoscale active area and efficiently convert it into an electrical signal. Here, we overcome all of those challenges in one device, by efficient coupling of a plasmonic antenna to hyperbolic phonon-polaritons in hexagonal-BN to highly concentrate mid-infrared light into a graphene pn-junction. We balance the interplay of the absorption, electrical and thermal conductivity of graphene via the device geometry. This approach yields remarkable device performance featuring room temperature high sensitivity (NEP of 82 pW= ffiffiffiffiffiffi Hz p ) and fast rise time of 17 nanoseconds (setup-limited), among others, hence achieving a combination currently not present in the state-of-the-art graphene and commercial mid-infrared detectors. We also develop a multiphysics model that shows very good quantitative agreement with our experimental results and reveals the different contributions to our photoresponse, thus paving the way for further improvement of these types of photodetectors even beyond mid-infrared range. ; F.H.L.K. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R& D (SEV-2015-0522), support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreement no. 785219 and no. 881603 Graphene Flagship for Core2 and Core3. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706). K.J.T. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 804349. R.H. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (national project RTI2018-094830-B-100 and the project MDM-2016-0618 of the Marie de Maeztu Units of Excellence Program) and the Basque Government (grant No. IT1164-19). S.C. acknowledges financial support from the Barcelona Institute of Science and Technology (BIST), the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya and the European Social Fund (L'FSE inverteix en el teu futur)—FEDER. D.E. acknowledges partial support from the Army Research Office MURI "Ab-Initio Solid-State Quantum Materials" Grant No. W911NF18-1-0431. J.G. was supported by the ARL-MIT Institute for Soldier Nanotechnologies (ISN). T.S. and L.M.M. acknowledge support by Spain's MINECO under Grant No. MAT2017-88358-C3-1-R and the Aragon Government through project Q-MAD. ; Peer Reviewed ; Postprint (published version)

Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials ; The ability to confine light into tiny spatial dimensions is important for applications such as microscopy, sensing and nanoscale lasers. While plasmons offer an appealing avenue to confine light, Landau damping in metals imposes a trade-off between optical field confinement and losses. We show that a graphene-insulator-metal heterostructure can overcome that trade-off, and demonstrate plasmon confinement down to the ultimate limit of the lengthscale of one atom. This is achieved by far-field excitation of plasmon modes squeezed into an atomically thin hexagonal boron nitride dielectric h-BN spacer between graphene and metal rods. A theoretical model which takes into account the non-local optical response of both graphene and metal is used to describe the results. These ultra-confined plasmonic modes, addressed with far-field light excitation, enables a route to new regimes of ultra-strong light-matter interactions. ; The authors thank Gerasimos Konstantatos and Valerio Pruneri for the intensive use of their respective FTIRs, very insightful discussions with Marco Polini, Thomas Christensen, Asger Mortenson and Javier Aizpurua on non-local effects and with Achim Woessner on simulation and modelling of graphene acoustic plasmonsmodes. Funding: We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2015-0522), support by Fundacio Cellex Barcelona, the Mineco grants Ramon y Cajal (RYC-2012-12281), Plan Nacional (FIS201347161-P and FIS2014-59639-JIN), and the Government of Catalonia trough the SGR grant (2014-SGR-1535). Furthermore, the research leading to these results has received funding from the European Union H2020 Programme under grant agreement no. 604391 Graphene Flagship, the ERC starting grant (307806, CarbonLight) and project GRASP ...