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Displaying 701 - 725 of 866

Dual comb-based characterization of rapidly tuned lasers

August 13, 2011
Author(s)
Fabrizio R. Giorgetta, Esther Baumann, Ian R. Coddington, William C. Swann, Nathan R. Newbury, Zeb Barber, Peter Roos
Time-resolved, high-accuracy and high-resolution spectroscopy of rapidly tuned cw lasers is critical to realizing their full potential for sensing, but is not possible with conventional spectrometers. We demonstrate a coherent dual-comb-based spectrometer

Precision spectroscopy with frequency combs at 3.4 ym

August 2, 2011
Author(s)
Esther Baumann, Fabrizio R. Giorgetta, William C. Swann, Alexander M. Zolot, Ian R. Coddington, Nathan R. Newbury
We discuss precision spectroscopy with a comb-based spectrometer at 3.4 υm. Our goal is to explore comb-based spectroscopy as an alternative method for fast, highly resolved, accurate measurements of gas line shapes. The spectrometer uses dual 1.5 υm

A circular dielectric grating for vertical extraction of single quantum dot emission

July 25, 2011
Author(s)
Marcelo I. Davanco, Matthew T. Rakher, Dieter Schuh, Antonio Badolato, Kartik A. Srinivasan
We demonstrate a suspended circular grating composed of partially etched annular trenches in a thin GaAs membrane, designed for e±cient and moderately broadband ( approx. 5 nm) extraction of emission from single InAs quantum dots. Simulations indicate that

Synchrotron radiation-based bilateral intercomparison of ultraviolet source calibrations

July 7, 2011
Author(s)
Uwe Arp, Zhigang Li, Ping-Shine Shaw, Mathias Richter, Roman Klein, Wolfgang Paustian, Reiner Thornagel
We report on a successful bilateral inter-comparison between the Physikalisch-Technische Bundesanstalt (PTB) and the National Institute of Standards and Technology (NIST). In both laboratories deuterium lamps were calibrated using the calculability of

Frequency-comb based approaches to precision ranging laser radar

June 20, 2011
Author(s)
Nathan R. Newbury, Tze-Ann Liu, Ian R. Coddington, Fabrizio R. Giorgetta, Esther Baumann, William C. Swann
The output of pulsed femtosecond lasers can be controlled to generate pulse trains with very precise timing and optical frequency. This source can be used in different ways to support precision coherent LIDAR. We will discuss several implementations of

Electromagnetic Energy Density in Dispersive and Dissipative Media

June 1, 2011
Author(s)
Frederico D. Nunes, Thiago Vasconcelos, Marcel Bezerra, John Weiner
The description of the energy density associated with an electromagnetic field propagating through matter must treat two different phenomena: dispersion, the variation of the refractive index with frequency, and dissipation, the loss of field energy by

Effects of Roughness on Scatterometry Signatures

May 26, 2011
Author(s)
Martin Foldyna, Thomas Germer, Brent Bergner
We used azimuthally-resolved spectroscopic Mueller matrix ellipsometry to study a periodic silicon line structure with and without artificially-generated line edge roughness (LER). Grating profiles were determined from multiple azimuthal configurations

Dual-comb based measurement of frequency agile lasers.

May 1, 2011
Author(s)
Ian R. Coddington, Fabrizio R. Giorgetta, Esther Baumann, William C. Swann, Nathan R. Newbury
Properly stabilized, frequency combs form high accuracy references across much of the optical spectrum. Here we employ dual frequency combs to harness this accuracy for fast and high resolution measurements of swept CW sources.

Microresonator based optical frequency combs

April 29, 2011
Author(s)
Scott A. Diddams, T. J. Klippenberg
Optical frequency combs based on mode-locked laser sources have provided unprecedented measurement capabilities for optical frequencies, enabling new applications in a wide range of topics that include atomic clocks, ultracold gases, molecular

Small-sized dichroic atomic vapor laser lock

April 21, 2011
Author(s)
Svenja A. Knappe, Changmin Lee, Geoffrey Z. Iwata, Eric Corsini, James M. Higbie, Micah P. Ledbetter, Dimitry Budkerl
Two, lightweight diode laser frequency stabilization systems designed for experiments in the field are described. Similar to a previous design, magnetic-field lines are contained within a magnetic shield enclosing permanent magnets and Rb cells, so that this

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
Displaying 701 - 725 of 866
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