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Displaying 401 - 425 of 615

Measurement Time and Statistics for a Noise Thermometer With a Synthetic-Noise Reference

August 1, 2008
Author(s)
David R. White, Samuel Benz, J Labenski, Sae Woo Nam, Jifeng Qu, H Rogalla, Weston L. Tew
This paper describes methods for reducing the statistical uncertainty in measurements made by noise thermometers using digital cross correlators, and in particular, for thermometers using pseudorandom noise for the reference signal. First, a discrete

Ultra fast quantum key distribution over a 97-km installed telecom fiber with wavelength-division-multiplexing clock synchronization

July 21, 2008
Author(s)
Akihiro Tanaka, Mikio Fujiwara, Sae Woo Nam, Yoshihiro Nambu, Seigo Takahashi, Wakako Maeda, Ken-ichiro Yoshino, Shigehito Miki, Burm Baek, Z. Wang, Akio Tajima, Masahide Sasaki, Akihisa Tomita
We demonstrated ultra fast BB84 quantum key distribution (QKD) transmission at 625 MHz clock rate through a 97 km field-installed fiber using practical clock synchronization based on wavelength-division-multiplexing (WDM). We succeeded in over-one-hour

High-efficiency, ultra-low-noise all-fiber photon pair source

June 20, 2008
Author(s)
Shellee D. Dyer, Martin J. Stevens, Burm Baek, Sae Woo Nam
We demonstrate an all-fiber photon pair source with the highest coincidence-to-accidental ratio (CAR) reported to date in the fiber optic telecom C-band. We achieve this through careful optimization of pair production efficiency as well as careful

Improvements in the NIST Johnson Noise Thermometry System

June 9, 2008
Author(s)
Samuel Benz, Horst Rogalla, Rod White, Jifeng Qu, Paul Dresselhaus, Wes L. Tew, Sae Woo Nam
We have developed a Johnson noise thermometry system that is calibrated by precision waveforms synthesized with a quantum-accurate voltage noise source (QVNS). Significant improvements to the QVNS and the cross-correlation measurement electronics have

Improving squeezing purity from a KNbO 3 crystal by temperature tuning

May 4, 2008
Author(s)
Thomas Gerrits, Tracy S. Clement, Scott Glancy, Richard P. Mirin, Sae Woo Nam, Emanuel Knill
We show a method to increase the purity of a squeezed state generated by a femtosecond laser and down-conversion crystal. The method relies on temperature tuning the down- and up-converting crystals, which changes the spatial and spectral output mode of

Designing high electron mobility transistor heterostructures with quantum dots for efficient, number-resolving photon detection

May 1, 2008
Author(s)
Mary A. Rowe, Eric Gansen, M. Greene, Danna Rosenberg, Todd E. Harvey, Mark Su, Robert Hadfield, Sae Woo Nam, Richard P. Mirin
We describe the design of the epitaxial layers for an efficient, photon-number-determining detector that utilizes a layer of self-assembled quantum dots as an optically addressable gate in a field-effect transistor. Our design features a dedicated

Distribution of time-energy entanglement over 100 km fiber using superconducting single-photon detectors

April 14, 2008
Author(s)
Qiang Zhang, Hiroki Takesue, Sae Woo Nam, Carston Langrock, Xiuping Xie, Burm Baek, Martin M. Fejer, Yoshihisa Yamamoto
In this letter, we report an experimental realization of distributing entangled photon pairs over 100 km of dispersion-shifted fiber. In the experiment, we used a periodically poled lithium niobate waveguide to generate the time-energy entanglement and

Demonstration of a quantum controlled-NOT gate in the telecom band

April 4, 2008
Author(s)
Jun Chen, Joseph B. Altepeter, Milja Medic, Fook L. Kim, Burc Gokden, Robert Hadfield, Sae Woo Nam, Prem Kumar
We present the first quantum controlled-NOT (CNOT) gate realized using a fiber-based indistinguishable photon-pair source in the 1.55 υm telecommunications band. Using this free-space CNOT gate, all four Bell states are produced and fully characterized by

Counting near-infrared single-photons with 95% efficiency

February 20, 2008
Author(s)
Adriana E. Lita, Aaron J. Miller, Sae Woo Nam
Single-photon detectors operating at visible and near-infrared wavelengths with high detection efficiency and low noise are a requirement for many quantum-information applications. Superconducting transition-edge sensors (TESs) are capable of detecting

Large sensitive-area NbN nanowire superconducting single-photon detectors fabricated on single-crystal MgO substrates

February 15, 2008
Author(s)
Shigehito Miki, Mikio Fujiwara, Masahide Sasaki, Burm Baek, Aaron Miller, Robert Hadfield, Sae Woo Nam, Zhen Wang
We report on the performance of large area NbN nanowire superconducting single-photon detectors (SSPDs). 20 x 20 υm 2 area SSPDs with 80 and 100 nm linewidths and 50% fill factor were fabricated in 4-nm-thick NbN films grown on single-crystal MgO