GRANOP · Graphene Nano-Photonics

Graphene Nano-Photonics

Graphene nano-photonics and strong light-matter interactions Graphene plasmons were predicted to possess simultaneous ultrastrong field confinement and very low damping, enabling new classes of devices for deep-subwavelength metamaterials, single-photon nonlinearities, extraordinarily strong light–matter interactions and nano-optoelectronic switches. In this context, we have realized several objectives with high impact implications: Objectives: 1. The generation and detection of graphene-based propagating surface plasmons in graphene. We have performed the first experiments revealed that graphene is an excellent host for guiding, confining and electrical manipulation of light at nanoscale dimensions. These highly desirable plasmonic capabilities remained so far elusive with other materials and therefore, these achievements will shape the future of optoelectronics, nano-photonics and modern optics. The achievements will open a new field at the border of solid-state physics, opto-electronics, quantum optics, and plasmonics. As demonstrated by this work, graphene plasmons can be used to electrically control light in a similar fashion as is traditionally achieved with electrons in a transistor. These capabilities, which until now were impossible with other existing plasmonic materials, enable new highly efficient nano-scale optical switches, which can perform calculations using light instead of electricity. In addition, the capability of trapping light in very small volumes could give rise to a new generation of nano-sensors with applications in diverse areas such as medicine and bio-detection, solar cells and light detectors, as well as quantum information processing. This result literally opens a new field of research and provides a first viable path towards ultrafast tuning of light, which was not possible until now. Reference: Optical nano-imaging of gate-tunable graphene plasmons J. Chen, M. Badioli, P. Alonso-González, S. Thongrattanasiri, F. Huth, J. Osmond, M. Spasenović, A. Centeno, A. Pesquera, P. Godignon, A. Zurutuza Elorza, N. Camara, F. J. García de Abajo, R. Hillenbrand, F. H. L. Koppens Nature 487, 77-81 (2012) 2. Tailoring extraordinary strong light-matter interactions with graphene By placing emitters in the vicinity of the graphene, lifetime modifications up to a factor of 100 were observed, and appealing physics involving universal energy transfer rates were demonstrated. Reference: Universal distance-scaling of nonradiative energy transfer to graphene L. Gaudreau, K. J. Tielrooij, G. E. D. K. Prawiroatmodjo, J. Osmond, F. J. García de Abajo, F. H. L. Koppens Nano Lett. 13, 2030-2035 (2013) Electrical detection: In addition, the coupling between the diamond nitrogen-vacancy center and graphene was exploited for electrical read-out of the spin. Here, ultra-fast photovoltage measurements (by using an Auston switch) were combined with fluorescence quenching. Interestingly, the energy transfer processed could be monitored in real-time. In addition, by manipulating the spin of the NV center, the energy transfer process could by controlled, and therefore the electrical signal. This enabled the first electrical read-out of the electron spin of a diamond NV center. Reference: Ultrafast electronic read-out of diamond NV centers coupled to graphene Andreas Brenneis, Louis Gaudreau, Max Seifert, Helmut Karl, Martin S. Brandt, Hans Huebl, Jose A. Garrido , Frank H.L. Koppens, Alexander W. Holleitner Nature Nanotechnol. 10, 135-139 (2014) 3. In-situ tuneability of the graphene plasmonic properties. The most clear demonstration of in-situ control of the plasmon velocity was shown by by exploiting graphene-boron nitride heterostructures. Due to the encapsulation of graphene, the intrinsic quality has been improved by an order of magnitude, and this also improved strongly the plasmonic properties. A detailed study on the loss mechanisms was added to this study, both theoretically and experimentally. Limitations of the plasmon losses beyond impurity scattering have been found. The work showed record high-quality factors for highly-confined plasmons, with lifetimes up to 0.5ps (20 times longer than for metals) and plasmon velocity tuning of more than a factor of two. Reference: Highly confined low-loss plasmons in graphene–boron nitride heterostructures A. Woessner, M. B. Lundeberg, Y. Gao, A. Principi, P. Alonso-González, M. Carrega, K. Watanabe, T. Taniguchi, G. Vignale, M. Polini, J. Hone, R. Hillenbrand, F. H. L. Koppens Nature Materials, 14, 421-425 (2015) 4. Graphene quantumelectrodynamics (QED) Graphene is also an excellent medium for strong light-matter interactions due to the high Purcell factors. We have demonstrated strong interactions between graphene and erbium as near-infrared nanoscale light-emitters. Because graphene is gapless with tunable carrier density, it can effectively behave as a semiconductor, a dielectric, or a metal. We exploit this to electrically control of optical emitter relaxation pathways. Specifically, we control whether emitter excitations are converted into either photons, electron-hole pairs, or plasmons with confinement to the graphene sheet below 15 nm. In addition, we have studied the energy transfer between molecules and graphene and find a universal scaling-law of the energy transfer rate, which contains no material parameters. This represents itself as a universal distance ruler for nanometer distances. Electrical Control of Optical Emitter Relaxation Pathways enabled by Graphene K.J. Tielrooij, L. Orona, A. Ferrier, M. Badioli, G. Navickaite, S. Coop, S. Nanot, B. Kalinic, T. Cesca, L. Gaudreau, Q. Ma, A. Centeno, A. Pesquera, A. Zurutuza, H. de Riedmatten, P. Goldner, F.J. García de Abajo, P. Jarillo-Herrero, F.H.L. Koppens Nature Physics 11.3, 281-287 (2015)

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