Compare Papers

Paper 1

Efficient Bell state analyzer for time-bin qubits with fast-recovery WSi superconducting single photon detectors

Raju Valivarthi, Itzel Lucio-Martinez, Allison Rubenok, Philip Chan, Francesco Marsili, Varun B. Verma, Matthew D. Shaw, J. A. Stern, Joshua A. Slater, Daniel Oblak, Sae Woo Nam, Wolfgang Tittel

Year

2014

Journal

arXiv preprint

DOI

arXiv:1410.4861

arXiv

1410.4861

We experimentally demonstrate a high-efficiency Bell state measurement for time-bin qubits that employs two superconducting nanowire single-photon detectors with short dead-times, allowing projections onto two Bell states, |Psi>- and |Psi+>. Compared to previous implementations for time-bin qubits, this yields an increase in the efficiency of Bell state analysis by a factor of thirty.

Open paper

Paper 2

Electroluminescence from a diamond device with ion-beam-micromachined buried graphitic electrodes

J. Forneris, A. Battiato, D. Gatto Monticone, F. Picollo, G. Amato, L. Boarino, G. Brida, I. P. Degiovanni, E. Enrico, M. Genovese, E. Moreva, P. Traina, C. Verona, G. Verona-Rinati, P. Olivero

Year

2014

Journal

arXiv preprint

DOI

arXiv:1407.7714

arXiv

1407.7714

Focused MeV ion microbeams are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as demonstrated in previous works with the fabrication of multi-electrode ionizing radiation detectors and cellular biosensors. In this work we investigate the suitability of the fabrication method for the electrical excitation of colour centres in diamond. Differently from photoluminescence, electroluminescence requires an electrical current flowing through the diamond sub-gap states for the excitation of the colour centres. With this purpose, buried graphitic electrodes with a spacing of 10 micrometers were fabricated in the bulk of a detector-grade CVD single-crystal diamond sample using a scanning 1.8 MeV He micro-beam. The current flowing in the gap region between the electrodes upon the application of a 250 V bias voltage was exploited as the excitation pump for the electroluminescence of different types of colour centres localized in the above-mentioned gap. The bright light emission was spatially mapped using a confocal optical microscopy setup. The spectral analysis of electroluminescence revealed the emission from neutrally-charged nitrogen-vacancy centres ($NV^0$, $λ_{ZPL}$ = 575 nm), as well as from cluster crystal dislocations (A-band, λ = 400-500 nm). Moreover, an electroluminescence signal with appealing spectral features (sharp emission at room temperature, low phonon sidebands) from He-related defects was detected ($λ_{ZPL}$ = 536.3 nm, $λ_{ZPL}$ = 560.5 nm); a low and broad peak around λ = 740 nm was also observed and tentatively ascribed to Si-V or GR1 centres. These results pose interesting future perspectives for the fabrication of electrically-stimulated single-photon emitters in diamond for applications in quantum optics and quantum cryptography.

Open paper