2019, Articolo in rivista, ENG
Schadler, Kevin G.; Ciancico, Carlotta; Pazzagli, Sofia; Lombardi, Pietro; Bachtold, Adrian; Toninelli, Costanza; Reserbat-Plantey, Antoine; Koppens, Frank H. L.
Solid-state quantum emitters are a mainstay of quantum nanophotonics as integrated single-photon sources (SPS) and optical nanoprobes. Integrating such emitters with active nanophotonic elements is desirable in order to attain efficient control of their optical properties, but it typically degrades the photostability of the emitter itself. Here, we demonstrate a tunable hybrid device that integrates state of the art lifetime-limited single emitters (line width similar to 40 MHz) and 2D materials at subwavelength separation without degradation of the emission properties. Our device's nanoscale dimensions enable ultrabroadband tuning (tuning range >400 GHz) and fast modulation (frequency similar to 100 MHz) of the emission energy, which renders it an integrated, ultracompact tunable SPS. Conversely, this offers a novel approach to optical sensing of 2D material properties using a single emitter as a nanoprobe.
2018, Articolo in rivista, ENG
Atzeni, Simone; Rab, Adil S.; Corrielli, Giacomo; Polino, Emanuele; Valeri, Mauro; Mataloni, Paolo; Spagnolo, Nicolo; Crespi, Andrea; Sciarrino, Fabio; Osellame, Roberto
Photon entanglement is at the basis of many protocols in photonic quantum technologies, from quantum computing to simulation and sensing. The generation of entangled photons in integrated waveguides is particularly advantageous due to the enhanced stability and more efficient nonlinear interaction. Here we realize an integrated source of entangled wavelength-degenerate photons based on the hybrid interfacing of photonic circuits in different materials, all inscribed by femtosecond laser pulses. We show that our source, based on spontaneous parametric down-conversion at the telecom wavelength, gives access to different classes of output states, allowing us to switch from path-entangled to polarization-entangled states with net visibilities above 0.92 for all selected combinations of integrated devices. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
2016, Articolo in rivista, ENG
Lohrmann, A.; Castelletto, S.; Klein, J. R.; Ohshima, T.; Bosi, M.; Negri, M.; Lau, D. W. M.; Gibson, B. C.; Prawer, S.; McCallum, J. C.; Johnson, B. C.
In this work, we present the creation and characterisation of single photon emitters at the surface of 4H-and 6H-SiC, and of 3C-SiC epitaxially grown on silicon. These emitters can be created by annealing in an oxygen atmosphere at temperatures above 550 degrees C. By using standard confocal microscopy techniques, we find characteristic spectral signatures in the visible region. The excited state lifetimes are found to be in the nanosecond regime in all three polytypes, and the emission dipoles are aligned with the lattice. HF-etching is shown to effectively annihilate the defects and to restore an optically clean surface. The defects described in this work have ideal characteristics for broadband single photon generation in the visible spectral region at room temperature and for integration into nanophotonic devices. (C) 2016 AIP Publishing LLC.
2011, Articolo in rivista, ENG
Pisanello, Ferruccio; Qualtieri, Antonio; Lemenager, Godefroy; Martiradonna, Luigi; Stomeo, Tiziana; Cingolani, Roberto; Bramati, Alberto; De Vittorio, Massimo
Colloidal nanocrystals, i.e. quantum dots synthesized trough wet-chemistry approaches, are promising nanoparticles for photonic applications and, remarkably, their quantum nature makes them very promising for single photon emission at room temperature. In this work we describe two approaches to engineer the emission properties of these nanoemitters in terms of radiative lifetime and photon polarization, drawing a viable strategy for their exploitation as room-temperature single photon sources for quantum information and quantum telecommunications.