Search Publications

Displaying 426 - 450 of 853

Scattering and Gradient Forces from the Electromagnetic Stress Tensor (subtitle) a limit obtained for a dielectric sphere

March 28, 2017

Author(s)

Zachary H. Levine, John J. Curry

Starting from an analytic expression for the force on a spherical particle in vacuum from the Maxwell Stress Tensor, as well as the Mie solution for the response of dielectric particles to an electromagnetic plane wave, the scattering force is derived as a

MOBY Review at Fiducial Reference Measurements for Satellite Ocean Color, Frascati, Italy, Feb 21 to 23, 2017

March 13, 2017

Author(s)

Kenneth Voss, B. Carol Johnson, Mark A. Yarbrough, Stephanie J. Flora, Michael Feinholz, Darryl Peters, Terrance Houlihan, Sean Mundell, Sandy Yarbrough, Art Gleason

This talk provided an overview of the MOBY project and the work we are doing now to move the MOBY instrumentation forward into the future. This is the first of 4 talks we gave at this workshop on various aspects of the MOBY project. The values of the MOBY

Radiometric Metrology for Ocean Color

March 13, 2017

Author(s)

Bettye C. Johnson

This talk covered the topics of uncertainty terminology (in brief), radiometric comparisons, gave an illustration of a spectral radiance scale realization, and concluded with a word on satellite system vicarious calibration (SVC).

Observation of optomechanical buckling phase transitions

March 1, 2017

Author(s)

Jacob M. Taylor, John R. Lawall, Haitan Xu, Utku Kemiktarak, Jingyun Fan, Stephen Ragole

Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets, and potential exotic quantum materials. Mechanical systems, such as relays and buckling transition spring switches can yield similar stability by exploiting

Structure and Dynamics of Bimodal Colloidal Dispersions in a Low-Molecular Weight Polymer Solution

February 24, 2017

Author(s)

Fan Zhang, Andrew J. Allen, Lyle E. Levine, De-Hao Tsai, Jan Ilavsky

We present an experimental study of the structural and dynamical properties of bimodal, micrometer-sized colloidal dispersions (size ratio ≈ 2) in an aqueous solution of low-molecular weight polymer (polyethylene glycol 2000) using synchrotron ultra-small

Enabling photoemission electron microscopy in liquids via graphene-capped microchannel arrays

February 8, 2017

Author(s)

Hongxuan Guo, Evgheni Strelcov, Alexander Yulaev, Jian Wang, Narayana Appathurai, Stephen Urquhart, John Vinson, Subin Sahu, Michael P. Zwolak, Andrei Kolmakov

Photoelectron emission microscopy (PEEM) is a powerful tool to spectroscopically access dynamic surface processes at the nanoscale but is traditionally limited to ultra-high or moderate vacuum conditions. Here, we develop a novel graphene-capped

Optical probe for nondestructive wafer-scale characterization of photonic elements

January 27, 2017

Author(s)

Thomas Michels, Vladimir A. Aksyuk

This article describes fabrication and operation of a microfabricated photonic waveguide loop probe for nondestructive evanescent coupling and localized testing of nanophotonic devices and circuits. A microfabricated 300 nm x 260 nm silicon (Si) waveguide

Static and Time-Resolved Terahertz Measurements of Photoconductivity in Solution-Deposited Ruthenium Oxide Nanofilms

January 25, 2017

Author(s)

Brian Alberding, Paul A. Desario, Adam D. Dunkelberger, Debra R. Rolison, Jeffrey C. Owrutsky, Edwin J. Heilweil

Thin film Ruthenium Oxide (RuO2) is a promising alternative material as a conductive electrode in electronic applications because its rutile crystalline form is metallic and highly conductive. Herein, a previously established solution-deposition multi

Direct Measurement of Dissipation in Phononic Crystal and Straight Tethers for MEMS Resonators

January 21, 2017

Author(s)

Vikrant J. Gokhale, Jason J. Gorman

This paper presents optical measurements of the dynamic strain profiles along the tethers of microelectromechanical resonators and relates them to quality factor. Such measurements allow for the quantification of tether dissipation and fair comparison

Dual Frequency Comb Laser Absorption Spectroscopy in a 16 MW Gas Turbine Exhaust

January 1, 2017

Author(s)

Paul J. Schroeder, Robert J. Wright, Sean Coburn, Bennett Sodergren, Kevin C. Cossel, Stefan Droste, Gar W. Truong, Esther Baumann, Fabrizio R. Giorgetta, Ian R. Coddington, Nathan R. Newbury, Gregory B. Rieker

Spectral dependence of carrier lifetimes in silicon for photovoltaic applications

December 21, 2016

Author(s)

John F. Roller, Yu-Tai Li, Mario Dagenais, Behrang H. Hamadani

Charge carrier lifetimes in photovoltaic-grade silicon wafers were measured by a spectral-dependent, quasi-steady-state photoconductance technique. Narrow bandwidth LEDs were used to excite excess charge carriers within the material, and the effective

Decoupling of a Neutron Interferometer from Temperature Gradients

December 16, 2016

Author(s)

Michael G. Huber, Muhammad D. Arif, P. Saggu, T. Mineeva, David Cory, Robert Haun, Ben Heacock, K Li, J. Nsofini, D. Sarenac, Chandra Shahi, V Skavysh, Mike Snow, S. Werner, A.R. Young, Dmitry Pushin

Neutron interferometry enables precision measurements that are typically operated within elaborate, multi-layered facilities which provide substantial shielding from environmental noise. These facilities are necessary to maintain the coherence requirements

Fabrication Process for an Optomechanical Transducer Platform with Integrated Actuation

December 8, 2016

Author(s)

Thomas Michels, Ivo Rangelow, Vladimir Aksyuk

This article reports a process for batch fabrication of a fiber pigtailed optomechanical transducer platform with overhanging cantilevers. The process combines nanophotonic, mechanical, and electrical elements with a combination of surface and bulk

A method for characterizing model fidelity in laser powder bed fusion additive manufacturing

November 30, 2016

Author(s)

Ibrahim Assouroko, Paul Witherell, Felipe LOPEZ

As Additive Manufacturing (AM) matures as a technology, predictive modeling methods have become increasingly sought after as a means for process planning, monitoring and control. For many, predictive modeling offers the potential to complement, and in some

Contact electrification of individual dielectric microparticles measured by optical tweezers in air.

November 29, 2016

Author(s)

Haesung Park, Thomas W. LeBrun

We have measured the charging of a dielectric microparticle after interacting with a glass substrate using optical tweezers to control the particle, measure its charge with sensitivity of a few electrons and precisely position the particle on the substrate

Optical amplitude and Phase Modulation Dynamics at the Single Photon Level in a Quantum Dot Ridge Waveguide

November 17, 2016

Author(s)

Galan A. Moody, Corey A. McDonald, Ari D. Feldman, Todd E. Harvey, Richard P. Mirin, Kevin L. Silverman

The amplitude and phase of a materials nonlinear optical response provide insight into the underlying electronic and exciton dynamics that determine its optical properties. Phase-sensitive nonlinear spectroscopy techniques are widely implemented to

A Planar Hyperblack Absolute Radiometer

November 14, 2016

Author(s)

John H. Lehman, Michelle S. Stephens, Malcolm G. White, Andreas Steiger, Christian Monte, Joerg Hollandt, Ivan Ryger, Mathias Kehrt, Marla L. Dowell

The absolute responsivity of a planar radiometer fabricated from micromachined silicon and having carbon nanotubes as the absorber and thermistor was measured in the visible and far infrared (free-field terahertz) wavelength range by means of detector

VECSEL systems for generation and manipulation of trapped magnesium ions

November 8, 2016

Author(s)

Shaun C. Burd, David T. Allcock, Tomi Leinonen, Jussi-Pekka Penttinen, Daniel H. Slichter, Raghavendra Srinivas, Andrew C. Wilson, Robert Jordens, Micrea Guina, Dietrich G. Leibfried, David J. Wineland

Experiments in atomic, molecular, and optical (AMO) physics rely on lasers at many different wave- lengths and with varying requirements on spectral linewidth, power and intensity stability. Vertical external-cavity surface-emitting lasers (VECSELs), when

Circular Photogalvanic Effect in Organometal Halide Perovskite CH3NH3PbI3

November 7, 2016

Author(s)

Junwen Li, Paul M. Haney

We study the circular photogalvanic effect in the organometal halide perovskite solar cell absorber CH$_3$NH$_3$PbI$_3$. The calculated photocurrent density is about $10^{-9}$ A/W, comparable to the previously studied quantum well and bulk Rashba systems

Report for Dedicated JPSS VIIRS Ocean Color Calibration/Validation Cruise December 2015

October 30, 2016

Author(s)

Michael Ondrusek, Veronica P. Lance, Eric Stengel, Menghua Wang, Zhongping Lee, Jianwei Wei, Junfang Lin, Chuanmin Hu, Charles Kovach, David English, Jennifer Cannizzaro, Alex Gilerson, Sam Ahmed, Carlos Carrizo, Ahmed El-Habashi, Robert Foster, Matteo Ottaviani, Robert Arnone, Sherwin Ladner, Wesley Goode, Ryan Vandermeulen, Nicholas Tufillaro, Jasmine Nahorniak, Curtiss Davis, Joaquim I. Goes, Kali McKee, Scott Freeman, Joaquin E. Chaves Cedeno, Kenneth Voss, B. Carol Johnson

Mueller matrix bidirectional reflectance distribution function measurements and modeling of textured silicon surfaces

October 25, 2016

Author(s)

Thomas Germer, Martin Foldyna, Zuzana Mrazkova

Surface texturing plays an important role in trapping light in photovoltaic materials. Understanding and modeling diffuse scatter from various textured silicon surfaces should aid in increasing light trapping in these materials, as well as improving

2016 Topical Meeting on Optical Interference Coatings: Manufacturing Problem Contest

October 21, 2016

Author(s)

Catherine C. Cooksey, Daniel Poitras, Li Li, Michael Jacobson

For the Manufacturing Problem contest held in conjunction with OSAs 2016 Topical Meeting on Optical Interference Coatings, participants were asked to design and fabricate on a provided substrate a coating with very specific (and rather peculiar)

Refractive index measurements of Ge

October 20, 2016

Author(s)

John H. Burnett, Simon G. Kaplan

A program has been started at NIST to make high-accuracy measurements of the infrared (IR) index properties of technologically important IR materials, in order to provide the IR optics community with updated values for the highest-quality materials now

Scattered Light Analysis of Birefringent Coatings for Distributed Polarization Rotators

October 20, 2016

Author(s)

Katelynn A. Sharma, Thomas Germer, Christopher Smith, Jonathan Zuegel, James B. Oliver, Thomas G. Brown

We characterize scattered light in polarization optics designed to maintain uniform illumination on target during spherical direct drive fusion experiments. An optical scatter instrument is used to measure the scatter distribution in the forward and

Goniometric and hemispherical reflectance and transmittance measurements of fused silica diffusers

October 11, 2016

Author(s)

Paul Lemaillet, Heather Patrick, Thomas Germer, Leonard Hanssen, B. Carol Johnson, Georgi T. Georgiev

Fused silica diffusers, made by forming scattering centers inside fused silica glass, can exhibit desirable optical properties, such as reflectance or transmittance independent of viewing angle, spectrally flat response into the ultraviolet wavelength