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Displaying 176 - 200 of 301

Innovations in Maximum Likelihood Quantum State Tomography

October 9, 2009
Author(s)
Scott C. Glancy, Emanuel H. Knill, Thomas Gerrits, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron J. Miller, Alan L. Migdall, Sae Woo Nam, Richard P. Mirin
At NIST we are engaged in an experiment whose goal is to create superpositions of optical coherent states (such superpositions are sometimes called "Schroedinger cat" states). We use homodyne detection to measure the light, and we apply maximum likelihood

High-efficiency photon-number resolving detectors based on hafnium transition-edge sensors

September 1, 2009
Author(s)
Adriana E. Lita, Brice R. Calkins, Lenson Pellouchoud, Aaron J. Miller, Sae Woo Nam
Generation of non-classical states of light is at the foundation of numerous quantum optics experiments and optical quantum information processing implementations. One such non-Gaussian optical quantum state can be obtained by photon subtraction from a

Measuring high-order coherences of chaotic and coherent optical states

August 24, 2009
Author(s)
Martin J. Stevens, Burm Baek, Eric Dauler, Andrew J. Kerman, Richard J. Molnar, Scott A. Hamilton, Karl Berggren, Richard P. Mirin, Sae Woo Nam
We demonstrate a new approach to measuring high-order temporal coherences that uses a four-element superconducting nanowire single-photon detector (SNSPD) in which four independent, single-photon-sensitive elements are interleaved over a single spatial

High-brightness, low-noise, all-fiber photon pair source

June 4, 2009
Author(s)
Shellee D. Dyer, Burm Baek, Sae Woo Nam
We demonstrate an all-fiber photon pair source for the critical telecom C-band. We achieve high pair generation rates in excess of 10 MHz while maintaining coincidence-to-accidental ratios (CARs) greater than 100. This is one of the brightest and lowest

Generation of optical Schrodinger cat states by number-resolved squeezed photon subtraction

May 31, 2009
Author(s)
Thomas Gerrits, Scott C. Glancy, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron J. Miller, Alan L. Migdall, Sae Woo Nam, Richard P. Mirin, Emanuel H. Knill
We have generated and measured an approximation of an optical Schrödinger cat state by photon subtraction from a squeezed state. Using single-photon avalanche photodiode detectors and photon-number-resolving transition edge sensors, we were able to extract

Third- and fourth-order coherences measured with a multi-element superconducting nanowire single-photon detector

May 29, 2009
Author(s)
Martin J. Stevens, Burm Baek, Eric Dauler, Andrew J. Kerman, Richard J. Molnar, Scott A. Hamilton, Karl Berggren, Richard P. Mirin, Sae Woo Nam
We demonstrate a technique for measuring third- and fourth-order coherences using a multi-element detector consisting of four independent, interleaved superconducting nanowire single-photon detectors, and observe strong bunching from a chaotic light source

1310 nm Differential Phase Shift QKD System Using Superconducting Single Photon Detectors

April 30, 2009
Author(s)
Xiao Tang, Lijun Ma, Sae Woo Nam, Burm Baek, Oliver T. Slattery, Alan Mink, Hai Xu, Tiejun Chang
We have implemented a differential-phase-shift (DPS) quantum key distribution (QKD) system at 1310 nm with superconducting single photon detectors (SSPD). The timing jitter of the SSPDs is small and its dark counts are very low. 1310 nm is an ideal quantum

Practical long-distance quantum key distribution system using decoy levels

April 30, 2009
Author(s)
Danna Rosenberg, Charles G. Peterson, Jim A. Harrington, Patrick R. Rice, N. Dallman, K. T. Tyagi, K. P. McCabe, Sae Woo Nam, Burm Baek, Robert Hadfield, Richard J. Hughes, Jane E. Nordholt
Quantum key distribution (QKD) has the potential for widespread real-world applications, but no secure long-distance experiment has demonstrated the truly practical operation needed to move QKD from the laboratory to the real world due largely to

Improvements in the NIST Johnson Noise Thermometry System

April 1, 2009
Author(s)
Samuel P. Benz, Jifeng Qu, Horst Rogalla, D. R. White, Paul D. Dresselhaus, Weston L. Tew, Sae Woo Nam
We have developed a Johnson noise thermometry (JNT) system that is calibrated by precision waveforms synthesized with a quantized voltage noise source (QVNS). Significant improvements to the QVNS and the cross-correlation measurement electronics have

Measuring intensity correlations with a two-element superconducting nanowire single-photon detector

November 24, 2008
Author(s)
Eric Dauler, Martin Stevens, Burm Baek, Richard J. Molnar, Scott A. Hamilton, Richard Mirin, Sae Woo Nam, Karl Berggren
Second-order intensity correlation measurements were made using a two-element superconducting nanowire single photon detector (SNSPD) without the need for an optical beam splitter. This approach can be used to obtain a 50-ps full width at half maximum

Long-distance entanglement-based quantum key distribution over optical fiber

November 10, 2008
Author(s)
Toshimori Honjo, Sae Woo Nam, Hiroki Takesue, Qiang Zhang, H. Kamada, Y. Nishida, O. Tadanaga, M. Asobe, Burm Baek, Robert Hadfield, Shigehito Miki, Mikio Fujiwara, Masahide Sasaki, Z. Wang, K. Inoue, Yoshihisa Yamamoto
We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-υm telecom band

Diagnosis of Pulsed Squeezing in Multiple Temporal Modes

August 26, 2008
Author(s)
Scott C. Glancy, Emanuel H. Knill, Thomas Gerrits, Tracy S. Clement, Martin J. Stevens, Sae Woo Nam, Richard P. Mirin
When one makes squeezed light by downconversion of a pulsed pump laser, many temporal / spectral modes are simultaneously squeezed by different amounts. There is no guarantee that any of these modes matches the pump or the local oscillator used to measure

Ultra-low-noise all-fiber photon pair source

August 21, 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.

Hanbury Brown-Twiss interferometry without a beamsplitter

August 19, 2008
Author(s)
Martin J. Stevens, Eric Dauler, Burm Baek, Richard J. Molnar, Scott A. Hamilton, Karl Berggren, Richard P. Mirin, Sae Woo Nam
We demonstrate Hanbury-Brown Twiss interferometry without a beamsplitter, by employing a single-mode optical fiber coupled to a multi-element superconducting nanowire single-photon detector.

Homodyne detection of optical cat states generated by squeezed light photon subtraction

August 19, 2008
Author(s)
Thomas Gerrits, Tracy S. Clement, Scott C. Glancy, Sae Woo Nam, Richard P. Mirin, Emanuel H. Knill
We have experimentally created and measured an optical Schrödinger Cat State. The method relies on single photon subtraction off a squeezed vacuum state and conditioning a homodyne measurement on the detection of that photon.

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
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