Recent results of a new microwave SQUID multiplexer (2009)
Hahn, Inseob, Limketkai, B., Bumble, B., LeDuc, H. G.
We are developing a proof-of-concept microwave SQUID multiplexer containing four SQUIDs coupled to GHz frequency resonant circuits and fed with a single microwave readout line. The resonators are...
Development of Low Noise THz SIS Mixer Using an Array of Nb/Al-AlN/NbTiN Junctions (2009)
Karpov, A., Miller, D., Stern, J. A., Bumble, B., LeDuc, H. G., Zmuidzinas, J.
We report the development of a low noise and broadband SIS mixer aimed for 1 THz channel of the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver (CASIMIR), designed for the...
Implementation of a Quantum Annealing Algorithm Using a Superconducting Circuit (2009)
Harris, R., Berkley, A. J., Johansson, J., Johnson, M. W., Lanting, T., Bunyk, P., ...
A circuit consisting of a network of coupled compound Josephson junction rf-SQUID flux qubits has been used to implement an adiabatic quantum optimization algorithm. It is shown that detailed...
Synchronization of Multiple Coupled rf-SQUID Flux Qubits (2009)
Harris, R., Brito, F., Berkley, A. J., Johansson, J., Johnson, M. W., Lanting, T., ...
A practical strategy for synchronizing the properties of compound Josephson junction rf-SQUID qubits on a multiqubit chip has been demonstrated. The impacts of small ($\sim1%$) fabrication variations...
R. A. Wyss, A. Neto, W. R. Mcgrath, B. Bumble, H. Leduc
spectral response of twin-slot antennas
Geometrical dependence of low frequency noise in superconducting flux qubits (2008)
Lanting, T., Berkley, A. J., Bumble, B., Bunyk, P., Fung, A., Johansson, J., ...
A general method for directly measuring the low-frequency flux noise (below 10 Hz) in compound Josephson junction superconducting flux qubits has been used to study a series of 85 devices of varying...
Probing Noise in Flux Qubits via Macroscopic Resonant Tunneling (2007)
Harris, R., Johnson, M. W., Han, S., Berkley, A. J., Johansson, J., Bunyk, P., ...
Macroscopic resonant tunneling between the two lowest lying states of a bistable RF-SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of...
B. S. Karasika, M. C. Gaidis, W. R. Mcgrath, B. Bumble, H. G. Leduc
The noise performance of a Nb hot-electron bolometer mixer at 2.5 THz has been investigated, The devices are fabricated from a 12 nm thick Nb film, and have a 0.30 pmxO. 15 urn in-plane size, thus...
J. Kawamura, D. Miller, J. Chen, J. Kooi, J. Zmuidzinas, B. Bumble, ...
We are currently exploring ways to improve the performance of SIS mixers above 700 GHz. One approach is to use NbTiN in place of Nb for all or some of the mixer circuitry. With its high gap frequency...
Bumble Frerking Laboratory, P. Febvrel, W. R. Mcgrath, P. Batelaan, H. G. Leduc, B. Bumble, ...
A receiver using an S1S waveguide mixer with two mechanical tuners has been characterized from 460 GHz to 640 GHz. The mixer uses S1S tunnel junctions with integrated superconductive RF circuits to...
Low Noise 1 THz–1.4 THz Mixers Using Nb/Al-AlN/NbTiN SIS Junctions (2007)
Karpov, A., Miller, D., Rice, F., Stern, J. A., Bumble, B., LeDuc, H. G., ...
We present the development of a low noise 1.2 THz and 1.4 THz SIS mixers for heterodyne spectrometry on the Stratospheric Observatory For Infrared Astronomy (SOFIA) and Herschel Space Observatory....
Pearson, J. C., Mehdi, I., Ward, J. S., Maiwald, F., Ferber, R. R., Leduc, H. G., ...
he Heterodyne Instrument for Far Infrared (HIFI) on ESA's Herschel Space Observatory utilizes a variety of novel RF components in its five SIS receiver channels covering 480- 1250 GHz and two HEB...
Low noise 1.2 THz SIS receiver (2004)
LeDuc, H. G., Karpov, A., Miller, D., Rice, F., Zmuidzinas, J., Stern, J. A., ...
We prevent the development of a low noise SIS mixer for the 1.1-1.25 THz heterodyne receiver of FIRST space radiotelescope.
Salez, M., Febvre, P., McGrath, W. R., Bumble, B., LeDuc, H. G.
A 600 GHz - 635 GHz waveguide SIS heterodyne receiver was built and used for astronomical observations at the Caltech Submillimeter Observatory (CSO) in Hawaii.
Superconducting Hot-Electron Bolometer Mixes at 0.5 Terahertz (2004)
Skalare, A., McGrath, W. R., Bumble, B., Leduc, H. G., Burke, P. J., Verheijen, A. A., ...
A 547 GHz SIS Receiver Employing a Submicron Nb Junction with an Integrated Matching Circuit (2004)
Febvre, P., McGrath, W., Leduc, H., Batelaan, P., Frerking, M., Hernichel, J., ...
The most sensitive heterodyne receivers used for millimeter wave and submillimeter wave radioastronomy employ superconductor-insulator-superconductor (SIS) tunnel junctions as the nonlinear mixing...
Febvre, P., McGrath, W., Batelaan, P., LeDuc, H., Bumble, B., Frerking, M., ...
This paper describes a receiver for radioastronomy applications in the 460 ??0-GHz range.
Salez, M., McGrath, W., Febvre, P., Bumble, B., LeDuc, H.
So far, the most sensitive heterodyne receivers in the millimeter-wave and submillimeter-wave frequency ranges have used the mixing response of the quasiparticle currents in SIS tunnel junctions.
A Superconducting Hot Electron Bolometer Mixer for 530 GHz (2004)
Skalare, A., McGrath, W.R., Bumble, B., LeDuc, H.G., Burke, P.J., Verheijen, A.A., ...
This paper describes a superconducting hot electron bolometer mixer that uses diffusion rather than interactions with phonons as a cooling mechanism for the hot electrons. The bolometer is a 0.14...
A Quasiparticle SIS Heterodyne Reciever at 600 GHz - 635 GHz (2004)
Salez, M., Febvre, P., McGrath, W.R., Bumble, B., LeDuc, H.G.
Superconducting Hot Electron Bolometer Mixers for Submillimeter Receivers (2004)
Skalare, A., McGrath, W.R., Bumble, B., LeDuc, H.G., Burke, P.J., Verheijen, A.A., ...
Febvre, P., Salez, M., McGrath, W. R., Bumble, B., LeDuc, H. G.
We have measured the noise temperature of heterodyne receivers employing
Niobium Superconducting Diffusion-Cooled Hot-Electron Bolometer MIxers Above 1 THz (2004)
Skalare, A., McGrath, W. R., Bumble, B., LeDuc, H. G., Burke, P. J., Schoelkopf, R. J., ...
Superconducting hot-electron bolometers are a promising option for low noise heterodyne detector systems at frequencies above 1THz. More...
Niobium Superconducting Diffusion-Cooled Hot-Electron Bolometer Mixers Above 1 THz (2004)
Skalare, A., McGrath, W. R., Bumble, B., LeDuc, H. G., Burke, P. J., Schoelkopf, R. J., ...
Large Bandwidth and Low Noise in a Diffusion-Cooled Hot-Electron Bolometer Mixer (2004)
Skalare, A., McGrath, W. R., Bumble, B., LeDuc, H. G., Burke, P. J., Verheijen, A. A., ...
X Heterodyne measurements have been made at 533 GHz using a novel superconducting hot-electron bolometer in a waveguide mixer. The bolometer is a 0.3 ??ong niobium microbridge with Tc=(approx. equal...
Low Noise in a Diffusion-Cooled Hot-Electron Mixer at 2.5 THz (2004)
A number of on-going astrophysical and atmospheric programs are aimed at spectroscopic exploration of the terahertz (THz) frequency range. There is an urgent need here for low-noise mixers for...
Low-noise and Wideband Hot-Electron Superconductive Mixers for THz Frequencies (2004)
Karasik, B., Skalare, A., Wyss, R., McGrath, W., Bumble, B., LeDuc, H., ...
Superconductive hot-electron bolometer (HEB) mixers have been built and tested in the frequency range from 1.1 THz to 2.5 THz.
Low-Noise and Wideband Hot-Electron Superconductive Mixers at THz Frequencies (2004)
Karasik, B., Skalare, A., McGrath, W., Bumble, B., LeDuc, H., Barner, J., ...
Fabrication of Nb/Al-Nx/NbTiN Junctions for SIS Mixer Applications Above 1 THz (2004)
Bumble, B., LeDuc, H. G., Stern, J. A.
We discuss the material processing limits of superconductor-insulator-superconductor (SIS) junctions with an energy gap high enough to enable THz heterodyne mixer detection.
Submillimeter-wave Spectral Response of Twin Slot Antennas Coupled to Hot Electron Bolometers (2004)
Wyss, R., Neto, A., McGrath, W., Bumble, B., LeDuc, H.
In this study we have measured mixers with a wide range of twin-slot antennas with slot lengths ranging from 26 meu up to 152 meu.
Fabrication of Nb/Al-N***subx***/NbTiN junctions for SIS mixer applications (2004)
Bumble, B., LeDuc, H. G., Stern, J. A., Megerian, K. G.
We discuss a processing technique for fabrication of superconductor-insulator-superconductor (SIS) junctions which typically exhibit a 3.5 mV sum-gap voltage.
Frequency-Domain Analysis of Diffusion-Cooled Hot-Electron Bolometer Mixers (2004)
Skalare, A., McGrath, W., Bumble, B., LeDuc, H.
A new theoretical model is introduced to describe heterodyne mixer conversion efficiency and noise (from thermal fluctuation effects) in diffusion-cooled superconducting hot-electron bolometers.
Wyss, R., Karasik, B., McGrath, W., Bumble, B., LeDuc, H.
Diffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz...
1.8 THz superconductive hot-electron bolometer mixer for Herschel (2004)
Kawamura, J. H., Harding, D., McGrath, W., Bumble, B., LeDuc, R., Focardi, P.
Tantalum hot-electron bolometers for low-noise heterodyne receivers (2004)
Skalare, A., McGrath, W., Bumble, B., LeDuc, H. G.
We describe superconducting diffusion-cooled hot-electron bolometers that were fabricated fromtantalum films grown on a thin niobium seed layer. The seed layer promotes single-phase growth of the Ta...
LOW-LOSS NbTiN FILMS FOR THz SIS MIXER TUNING CIRCUITS (1998)
Kooi Stern Chattopadhyay, J. W. Kooi, J. A. Stern, G. Chattopadhyay, H. G. Leduc, B. Bumble, ...
Recent results at 1 THz using normal-metal tuning circuits have shown that SIS mixers can work well up to twice the gap frequency of the junction material (niobium). However, the performance at 1 THz...