Danna Rosenberg

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Superconducting nanowire single photon detectors (SNSPDs) have separately demonstrated high efficiency, low noise, and extremely high speed when detecting single photons. However, achieving all of these simultaneously has been limited by detector subtleties and tradeoffs. Here, we report an SNSPD system with <80 ps timing resolution, kHz noise count rates,(More)
Use of low-noise detectors can both increase the secret bit rate of long-distance quantum key distribution (QKD) and dramatically extend the length of a fibre optic link over which secure key can be distributed. Previous work has demonstrated use of ultra-low-noise transitionedge sensors (TESs) in a QKD system with transmission over 50 km. In this work, we(More)
Citation Dixon, P. Ben, et al. "Heralding efficiency and correlated-mode coupling of near-IR fiber-coupled photon pairs. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how(More)
The scalable application of quantum information science will stand on reproducible and controllable high-coherence quantum bits (qubits). Here, we revisit the design and fabrication of the superconducting flux qubit, achieving a planar device with broad-frequency tunability, strong anharmonicity, high reproducibility and relaxation times in excess of 40 μs(More)
Experimental restrictions imposed on the collection and detection of shortwave-infrared photons (SWIR) have impeded single molecule work on a large class of materials whose optical activity lies in the SWIR. Here we report the successful observation of room-temperature single nanocrystal photoluminescence at SWIR wavelengths using a highly efficient(More)
The understanding of the photophysics of visibleemitting colloidal nanocrystals (NCs) has long been aided by single-molecule studies of their emission. Until recently, no suitable detection technologies have existed for corresponding studies of shortwave-infrared (SWIR) emitters. Now, the use of superconducting nanowire single-photon detectors (SNSPDs)(More)
In this paper we present a design for a photoncounting optical receiver&#x2014;based on superconducting NbN nanowire detector arrays&#x2014;that will be employed in the ground terminal for the NASA Lunar Laser Communications Demonstration. The ground receiver is designed with four, 40 cm apertures, each coupled to a novel multi-mode polarization-maintaining(More)
Tungsten thin films can form in one of two crystal structures: alpha (bcc), with a superconducting transition temperature ( c ) of 15 mK, and beta (A15), with a c between 1 and 4 K. Films with intermediate c s are composed of both alpha and beta phases. We have investigated how to tune the film c in order to obtain certain values ( c 100mK) suitable for the(More)
Dynamical error suppression techniques are commonly used to improve coherence in quantum systems. They reduce dephasing errors by applying control pulses designed to reverse erroneous coherent evolution driven by environmental noise. However, such methods cannot correct for irreversible processes such as energy relaxation. We investigate a complementary,(More)
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