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Superconducting nanowire single photon detectors (SNSPDs) have become a mature technology for single-photon detection with excellent performance [...]

We demonstrate the strong coupling between a single electron spin in silicon and a single photon in a superconducting microwave cavity. Using the same cavity we perform rapid high-fidelity single-shot readout of two-electron spin states.

We experimentally investigate the performance of NbTiN superconducting nanowire single photon detectors above the base temperature of a conventional Gifford-McMahon cryocooler (2.5 K). By tailoring design and thickness (8 - 13 nm) of the detectors, high performance, high operating temperature, single-photon detection from the visible to telecom wavelengths are demonstrated. At 4.3 K, a detection efficiency of 82 % at 785 nm wavelength and a timing jitter of 30 ± 0.3 ps are achieved. In addition, for 1550 nm and similar operating temperature we measured a detection efficiency as high as 64 %. Finally, we show that at temperatures up to 7 K, unity internal efficiency is maintained for the visible spectrum. Our work is particularly important to allow for the large scale implementation of superconducting single photon detectors in combination with heat sources such as free-space optical windows, cryogenic electronics, microwave sources and active optical components for complex quantum optical experiments and bio-imaging.

In this work, a novel hybrid fabrication method for graphene quantum dot devices with minimum feature sizes of ~3nm and high yield is described. It is a combination of e-beam lithography and direct milling with the sub-nm focused helium ion beam generated by a helium ion microscope. The method is used to fabricate graphene quantum dot devices contacted with metal to allow electrical characterization. An annealing step is described that reduces hydrocarbon contamination on the sample surface and allows complete removal of graphene by the helium ion beam and therefore successful isolation of side gates. The electrical characterization of the final device demonstrates the successful fabrication of the first electrically characterized He-ion beam patterned graphene device. The highly controllable, fine scale fabrication capabilities offered by this approach could lead to a more detailed understanding of the electrical characteristics of graphene quantum devices and pave the way towards room-temperature operable graphene quantum dot devices.

In this paper we first present a new hybrid fabrication process of downscaled graphene nanodevices based on direct ultrafine milling process by using atomic-size helium ion beam and the electron beam lithography process. We then describe the bilayer graphene single carrier transistors (GSCTs) and their Coulomb oscillation characteristics at 1.7 K. Unique double current peak structures were observed in the Coulomb oscillation which are attributable to single carrier tunneling via vertically stacked double charging islands. Finally we demonstrate a mechanically stable graphene nano-electro-mechanical (GNEM) switch fabricated using a simple etching-free method with polymer sacrificial spacer. Switch-ON and OFF operations are achieved in a reversible manner.