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Physics

Optical physics and communications

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Displaying 751 - 775 of 861

Molecular spectroscopy with frequency combs

March 1, 2010
Author(s)
Ian R. Coddington
Pulsed femtosecond frequency combs are rapidly developing as a powerful spectroscopic tool. As a spectroscopic source stabilized frequency combs potentially offer broad spectral coverage, near perfect frequency accuracy, low timing jitter and broadband

Sensitivity Comparison of Mx and Frequency Modulated Bell-Bloom Cs Magnetometers in a Micro-Fabricated Cell

February 1, 2010
Author(s)
Ricardo Jimenez Martinez, William C. Griffith, Ying-ju Wang, Svenja A. Knappe, John E. Kitching, Ken Smith, Mark Prouty
We compare the sensitivity performance of two optically pumped atomic magnetometers based on the Mx and frequency-modulated Bell-Bloom configurations. The Cs magnetometers are implemented using a millimeter-scale microfabricated vapor cell in a

Infrared time domain spectroscopy with synchronized frequency combs

January 29, 2010
Author(s)
Nathan R. Newbury, Ian R. Coddington, William C. Swann
We describe a frequency-comb based system for time-domain spectroscopy in the near infrared. Our configuration implements synchronous, repetitive sampling of the time domain signature for real-time coherent signal averaging and improved signal-to-noise

Linewidth narrowing and Purcell enhancement in photonic crystal cavities on an Er-doped silicon nitride platform

January 25, 2010
Author(s)
Yiyang Gong, Maria Makarova, Selcuk Yerci, Rui Li, Martin Stevens, Burm Baek, Sae Woo Nam, Robert Hadfield, Sander N. Dorenbos, Val Zwiller, Luca Dal Negro, Jelena Vuckovic
Light emission at 1.54 mm from an Er-doped amorphous silicon nitride layer coupled to photonic crystal resonators at cryogenic and room temperatures and under varying optical pump powers has been studied. The results demonstrate that small mode volume

Polarized Optical Scattering Signatures from Biological Materials

January 11, 2010
Author(s)
W. E. Martin, E. Hesse, J. H. Hough, William Sparks, C. S. Cockell, Z. Ulanowski, Thomas Germer, B. Kaye
The polarization of laser light backscattered from biological samples has been measured over the wavelength range 350 to 850nm. Incident circular, linearly polarized, and unpolarized light produces significant spectrally prominent scattered polarizations

Progress Toward Corrugated Feed Horn Arrays in Silicon

December 16, 2009
Author(s)
Joseph W. Britton, Ki W. Yoon, James A. Beall, Daniel T. Becker, Hsiao-Mei Cho, Gene C. Hilton, Michael D. Niemack, Kent D. Irwin
We are developing monolithic arrays of corrugated feed horns fabricated in silicon for dual-polarization single mode operation at 90, 145 and 220 GHz. The arrays consist of hundreds of platelet feed horns assembled from gold coated stacks of micromachined

Quasi-phasematched Second Harmonic Generation in GaAs Microdisks

November 15, 2009
Author(s)
Paulina S. Kuo, W Fang, Glenn S. Solomon
We discuss design and tuning of second-harmonic generation in GaAs microdisks. Quasi-phasematching can be achieved in the microdisk geometry without external domain inversions, but efficient nonlinear optical mixing requires that all waves be resonant

Optical frequency stabilization of a 10 GHz Ti:sapphire frequency comb by saturated absorption spectroscopy in 87Rubidium

November 4, 2009
Author(s)
Dirk Heinecke, Albrecht Bartels, Tara M. Fortier, Danielle Braje, Leo Hollberg, Scott A. Diddams
The high power per mode of a recently-developed 10 GHz femtosecond Ti:sapphire frequency comb permits nonlinear Doppler-free saturation spectroscopy in 87Rubidium with a single mode of the comb. We use this access to the natural linewidth of the Rubidium

Preparation of Dicke States in an Ion Chain

November 2, 2009
Author(s)
David Hume, Chin-Wen Chou, Till P. Rosenband, David J. Wineland
We have investigated theoretically and experimentally a method for preparing Dicke states in trapped atomic ions. We consider a linear chain of N ion qubits that is prepared in a particular Fock state of motion, jmi. The m phonons are removed by applying a

Effect of Surface Modes on Photon Propagation through Dielectric Bandgaps

October 28, 2009
Author(s)
Natalia Malkova, Sergey V. Polyakov, Alan L. Migdall, Garnett W. Bryant
We investigate the Hartman saturation effect of photons traveling through barriers created by bandgaps of multilayer stacks. In particular, we investigate theoretically the recently observed jumps in photon transversal times due to adding a single layer

Uncooled, Millimeter-Scale Atomic Magnetometers with Femtotesla Sensitivity

October 26, 2009
Author(s)
John E. Kitching, Svenja A. Knappe, William C. Griffith, Jan Preusser, V Gerginov, Peter D. Schwindt, Vishal Shah, Ricardo Jimenez Martinez
We summarize recent results at NIST to develop high-performance yet highly miniaturized magnetic sensors based on atomic vapors confined in microfabricated alkali vapor cells. These sensors currently achieve sensitivities in the range of a few tens of

Measuring the EUV-induced contamination rates of TiO2-capped multilayer optics by anticipated production-environment hydrocarbons

October 1, 2009
Author(s)
Shannon B. Hill, Nadir S. Faradzhev, Charles S. Tarrio, Thomas B. Lucatorto, Robert A. Bartynski, B. V. Yakshinskiy, T. E. Madey
The primary, publicly reported cause of optic degradation in pre-production extreme-ultraviolet (EUV) lithography systems is carbon deposition. This results when volatile organics adsorb onto optic surfaces and then are cracked by EUV-induced reactions

Relative Photon-to-Carrier Efficiencies of Alternating Nanolayers of Zinc Phthalocyanine and C60 Multilayer Films Assessed by Time-Resolved Terahertz Spectroscopy

October 1, 2009
Author(s)
Okan Esenturk, Joseph S. Melinger, Paul A. Lane, Edwin J. Heilweil
Alternating multi-layer and 1:1 blended films of zinc phthalocyanine (ZnPc)and buckminsterfullerene (C60) were investigated as model active layers for solar cells by Time-Resolved Terahertz Spectroscopy (TRTS). Relative photon-to-carrier efficiencies 2

Generation and Mixing of Subfemtoliter Aqueous Droplets on Demand

August 27, 2009
Author(s)
Kristian Helmerson, Jianyong N. Tang, Ana Jofre, Rani Kishore, Joseph E. Reiner, Mark E. Greene, Geoffrey M. Lowman, John Denker, Christina N. Willis, Lori Goldner
We describe a novel method of generating monodisperse sub-femtoliter aqueous droplets on demand by means of piezoelectric injection. Droplets with volumes down to 200 aL are generated by this technique. The droplets are injected into a low refractive index

The Extension of the NIST BRDF Scale from 1100 nm to 2500 nm

August 21, 2009
Author(s)
Howard W. Yoon, David W. Allen, George P. Eppeldauer, Benjamin K. Tsai
Measurements of bi-directional reflectance factor for diffuse reflectance from 1100 nm to 2500 nm using extended-range indium gallium arsenide (exInGaAs) detectors in the NIST Spectral Tri-function Automated Reference Reflectometer (STARR) facility are

Coalescing GSICS Correction Coefficients

August 14, 2009
Author(s)
Ruediger Kessel
We would like to present a technique to adjust the uncertainty estimates of each point in a time series, so that the variance of the time series is consistent with the uncertainty estimates of its component points. This would allow the uncertainty of the

Developing an Uncertainty Analysis for Optical Scatterometry

August 3, 2009
Author(s)
Thomas A. Germer, Heather J. Patrick, Richard M. Silver, Benjamin Bunday
This article describes how an uncertainty analysis may be performed on a scatterometry measurement. A method is outlined for propagating uncertainties through a least-squares regression. The method includes the propagation of the measurement noise as well

Tracking down sources of carbon contamination in EUVL exposure tools

August 3, 2009
Author(s)
Charles S. Tarrio, Robert E. Vest, Thomas B. Lucatorto, R. Caudillo
Optics in EUVL exposure tools are known to suffer reflectivity degradation, mostly from the buildup of carbon. The sources of this carbon have been difficult to identify. Vacuum cleanliness is normally monitored with a residual gas analyzer, but this has

Coherent linear optical sampling at over 15 bits of resolution

July 15, 2009
Author(s)
Ian R. Coddington, William C. Swann, Nathan R. Newbury
Linear optical sampling characterizes a sample by measuring the distortions on a transmitted optical field, thereby quantifying the sample's optical response. By exploiting the high mutual coherence between two phase-locked femtosecond fiber lasers, we

Intensity dynamics in semiconductor laser arrays

July 13, 2009
Author(s)
Kevin L. Silverman, Mingming M. Feng, Richard P. Mirin, Steven T. Cundiff, Matt Williams, J. Nathan N. Kutz
The dynamics of a five-emitter semiconductor laser array is studied theoretically with steady-state, oscillatory, and chaotic behaviors achieved. This provides a design tool for achieving oscillations whose frequency is related to injection current.

Using the nonlinear Schroedinger equation for precision optical measurements

July 6, 2009
Author(s)
Nathan R. Newbury, Esther Baumann, Ian R. Coddington, Fabrizio R. Giorgetta, William C. Swann
Frequency combs produce light that is both broadband and highly coherent. However, their operation relies on the nonlinear Schroedinger equation, in particular to achieve the broad spectral output. Because it is a highly nonlinear system, this comb output
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