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Physics

Optical physics and communications

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Displaying 701 - 725 of 853

Nested Uncertainties and Hybrid Metrology to Improve Measurement Accuracy

April 18, 2011
Author(s)
Richard M. Silver, Nien F. Zhang, Bryan M. Barnes, Hui Zhou, Jing Qin, Ronald G. Dixson
In this paper we present a method to combine measurement techniques that reduce uncertainties and improve measurement throughput. The approach has immediate utility when performing model-based optical critical dimension measurements. When modeling optical

Separation of Empty and Water-Filled Single-Wall Carbon Nanotubes

April 11, 2011
Author(s)
Jeffrey A. Fagan, Jeffrey R. Simpson, JiYeon Huh, Jeffrey Blackburn, Larsen A. Brian, Josh M. Holt, Angela R. Hight Walker
The separation of empty and water-filled laser ablation and electric arc synthesized nanotubes is reported. Centrifugation of these large-diameter nanotubes dispersed with sodium deoxycholate using specific conditions produces isolated bands of empty and

Characterizing arbitrary CW waveforms with 1500 THz/s chirp rates

April 5, 2011
Author(s)
Ian R. Coddington, Fabrizio R. Giorgetta, Esther Baumann, William C. Swann, Nathan R. Newbury
A Dual frequency comb interferometer was constructed to monitor cw laser chirp rates exceeding 1500 THz/s with MHz level resolution and accuracy over a 3 THz spectral sweep. Monitoring of the chirped laser is continuous. Additionally, absolute frequency

Characterization of an actively linearized ultra-broadband chirp laser with a fiber-laser optical frequency comb

March 25, 2011
Author(s)
Zeb W. Barber, Jason Dahl, Peter Roos, Randy Reibel, Nathan Greenfield, Fabrizio R. Giorgetta, Ian R. Coddington, Nathan R. Newbury
The optical frequency sweep of an actively linearized, ultra-broadband, chirped laser source is characterized through optical heterodyne detection against fiber-laser frequency combs. Frequency sweeps were measured over approximately 4.7 THz bandwidths

Polarization-Entangled Photon Pairs From a Periodically Poled Cystalline Waveguide

March 23, 2011
Author(s)
Zachary H. Levine, Jingyun Fan, Jun Chen, Alan L. Migdall
A proposal is made for the generation of polarization-entangled photon pairs from a periodically poled crystal. The theory is formulated in terms of colinear propagation for application to waveguides. The key feature of the theory is the use of type 2

Introduction to special issue on single-photon technologies

March 10, 2011
Author(s)
Alan L. Migdall, Sergey V. Polyakov, Jingyun Fan, Ivo P. Degiovanni, Jessica Cheung
This special issue accompanies the 4th international conference on single-photon technologies held at the National Institute of Standards and Technology (NIST) Boulder in November 2009. This community has met every two years at national metrology

Real-time polarization microscopy for probing local distributions of biomolecules

February 28, 2011
Author(s)
Jeeseong Hwang, Ji Y. Lee, John F. Lesoine, Hyeong G. Kang, Matthew L. Clarke, Robert C. Chang
We present real-time, full-field, fluorescence polarization microscopy and its calibration and validation methods to monitor the absorption dipole orientation of fluorescent molecules. A quarter-wave plate, in combination with a liquid crystal variable

Rapid, high resolution frequency comb measurements

February 13, 2011
Author(s)
Ian R. Coddington, Fabrizio R. Giorgetta, Esther Baumann, William C. Swann, Nathan R. Newbury
Frequency combs serve as an extremely high accuracy reference across broad portions of the optical spectrum. Dual frequency combs harness this accuracy and allow for fast and highly flexible measurements of passive and active sources.

Bilateral NIST-PTB Comparison of Spectral Responsivity in the VUV

January 20, 2011
Author(s)
Uwe Arp, Ping-Shine Shaw, Zhigang Li, Alexander Gottwald, Mathias Richter
To compare the calibration capabilities for the spectral responsivity in the vacuum-ultraviolet spectral region between 135 nm and 250 nm, PTB and NIST agreed on a bilateral comparison. Calibrations of semiconductor photodiodes as transfer detectors were

Electron Vortex Beams with High Quanta of Orbital Angular Momentum

January 14, 2011
Author(s)
Benjamin James McMorran, Amit K. Agrawal, Ian M. Anderson, Andrew A. Herzing, Henri J. Lezec, Jabez J. McClelland, John Unguris
Analogous to vortices in light optical beams, electron optical beams with helical wavefronts carry orbital angular momentum and promise new capabilities for electron microscopy and other applications. We use nanofabricated diffraction holograms in an

Synthetic Electric and Magnetic Fields for Ultracold Neutral Atoms

January 1, 2011
Author(s)
William D. Phillips, Yu-Ju Lin, Robert L. Compton, Karina K. Jimenez Garcia, Abigail R. Perry, James V. Porto, Ian B. Spielman
We use Raman coupling between magnetic sublevels of a 87Rb Bose-Einstein condensate (BEC) to create an effective vector gauge field for the neutral atoms. They behave as if they were charged particles in a magnetic vector potential. With appropriate

Defining Common Reference Channels for Geostationary Infrared Imagers

December 31, 2010
Author(s)
Tim Hewison, Ruediger Kessel
This article follows up the theoretical considerations presented above with an example applied to the infrared channels of geostationary imagers. The uncertainties, u(deltaLr), introduced by the process of spectral conversion to Common Reference Channels

Common Reference Channels for Metrological Comparability

December 20, 2010
Author(s)
Ruediger Kessel, Tim Hewison
In this article we discuss the effect of the choice of reference during calibration on later use of the calibrated results, and how a reference should be chosen to support later use of the data. Starting from the concept of metrological comparability we

Generalized ellipsometry of artificially designed line width roughness

December 10, 2010
Author(s)
Martin Foldyna, Thomas A. Germer, Brent Bergner, Ronald G. Dixson
We use azimuthally-resolved spectroscopic Mueller matrix ellipsometry to study a periodic silicon line structure with and without artificially-generated line width roughness (LWR). We model the artificially perturbed grating using 1D and 2D rigorous

Fast high-resolution frequency agile spectroscopy of laser sources

October 24, 2010
Author(s)
Fabrizio R. Giorgetta, Ian R. Coddington, Esther Baumann, William C. Swann, Nathan R. Newbury
Time-resolved, high-accuracy and high-resolution spectroscopy of frequency-agile cw lasers is critical to realizing their full potential for sensing, but is not possible with conventional spectroscopy methods. We demonstrate a dual comb-based spectrometer

The evolving optical frequency comb

October 22, 2010
Author(s)
Scott A. Diddams
Much as natural historians search for the first roots of our human race, curiosity drives the laser scientist to pursue the roots of his or her own field. This is especially the case in this year where our community celebrates the 50th anniversary of the

Dual frequency comb Fourier transform spectroscopy

October 12, 2010
Author(s)
Ian R. Coddington, William C. Swann, Nathan R. Newbury
Dual coherent frequency combs can be used in Fourier transform spectroscopy (FTS) to generate the full optical response of a sample with high frequency, and time, accuracy and resolution. The approach can be viewed equally well as a multiheterodyne

Sub-micron force detection using optically-cooled levitated microspheres

September 3, 2010
Author(s)
Andrew Geraci, Scott B. Papp, John E. Kitching
We propose an experiment using optically trapped and cooled dielectric microspheres for the detection of short-range forces. The center-of-mass motion of a microsphere trapped in vacuum can experience extremely low dissipation and quality factors of 10 12

Separation and Metrology of Nanoparticles by Nanofluidic Size Exclusion

August 11, 2010
Author(s)
Samuel M. Stavis, Jon C. Geist, Michael Gaitan
A nanofluidic approach to the separation and metrology of nanoparticles is demonstrated. Advantages of this approach include nanometer-scale resolution, nanometer-scale to submicrometer-scale range, mitigation of hydrodynamic and diffusional limitations to

Superconducting Transition-Edge Sensors for Waveguide Coupled Single Photon Detection

July 25, 2010
Author(s)
Anna E. Fox, Adriana E. Lita, Brice R. Calkins, Kevin L. Silverman, Richard P. Mirin, Sae Woo Nam
We present the design and important preliminary superconducting properties of an evanescently coupled number resolving single photon detector operating near 1550 nm in development for integration into a silicon-on-insulator waveguide based optical system.
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