An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Line width roughness (LWR) has been identified as a potential source of uncertainty in scatterometry measurements, and characterizing its effect is required to improve the method s accuracy and to make measurements traceable. In this work, we extend
Charles S. Tarrio, Steven E. Grantham, Marc J. Cangemi, Robert E. Vest, Thomas B. Lucatorto, Noreen Harned
As part of its role in providing radiometric standards in support of industry, NIST has been active in advancing extreme ultraviolet dosimetry on various fronts. Recently, we undertook a major effort in accurately measuring the sensitivity of three extreme
Improved detector technology in the past two decades opened a new era in the field of optical radiation measurements. Lower calibration and measurement uncertainties can be achieved with modern detector/radiometer standards than traditionally used source
Recent developments in optical microscopy promise to advance optical metrology and imaging to unprecedented levels through theoretical and experimental development of a new measurement technique called "scatterfield optical imaging". ". Current metrology
Paul A. Williams, Tasshi Dennis, Ian R. Coddington, William C. Swann, Nathan R. Newbury
We demonstrate linear optical sampling measurements optimized for characterization of the signals produced by optical components. By sampling the optical electric field before and after the component, we isolate the full vector field (phase and amplitude)
The simulation of microscope images computed from scattered fields determined using integral equations depend on a number of parameters that are not related to the scatterer or to the microscope but are choices made for the computation method. The effect
Singular integral equations that determine the exact fields scattered by a dielectric or conducting finite strip on a substrate are presented. The computation of the image of such a scatterer from these fields by Fourier optics methods is also shown.
Nathan D. Lemke, Andrew Ludlow, Zeb Barber, N Poli, C.W. Hoyt, Long-Sheng Ma, Jason Stalnaker, Christopher W. Oates, Leo Hollberg, James C. Bergquist, A. Brusch, Tara Fortier, Scott Diddams, Thomas P. Heavner, Steven R. Jefferts, Tom Parker
We describe the development and latest results of an optical lattice clock based on neutral Yb atoms, including investigations based on both even and odd isotopes. We report a fractional frequency uncertainty below 10 -15 for 171Yb.
Bettye C. Johnson, James J. Butler, Scott J. Janz, Robert D. Saunders, John W. Cooper, Matthew G. Kowalewski, R Barnes
In June 2007, a spherical integrating source was calibrated in the National Aeronautics and Space Administration(NASA) Goddard Space Flight Centers (GSFC) Calibration Facility as part of the prelaunch characterization program for the NPOESS Preparatory
Sergey Polyakov, Alan L. Migdall, Paul D. Lett, David Papoular, Pierre Clade, Colin McCormick
We report a prediction for the delay measured in an optical tunneling experiment using Hong-Ou-Mandel (HOM) interference, taking into account the Goos-Hanchen shift generalized to frustrated total internal reflection situations. We precisely state
George P. Eppeldauer, Carl C. Miller, Yoshihiro Ohno
Two reference and three working standard tristimulus colorimeters have been developed at the National Institute of Standards and Technology (NIST) to utilize the recently introduced detector based colorimeter calibration method [1]. The tristimulus
Daneesh O. Simien, Jeffrey A. Fagan, Jack F. Douglas, Kalman D. Migler, Jan Obrzut
Thin layers of length-sorted single wall carbon nanotubes (SWNT) were formed in to a buckypaper sample through vacuum filtration. These length sorted samples exhibit sharp changes in their optical and conductivity (S) properties with increasing SWNT
A technique using artificial neural networks to simultaneously identify OSNR, CD, and PMD from eye-diagram parameters is demonstrated both via simulation and experimentally in 40 Gb/s OOK and DPSK systems. A correlation coefficient of 0.99 is obtained for
Simon G. Kaplan, Leonard M. Hanssen, Enrique J. Iglesias
We have developed a goniometric reflectometer using a Fourier-transform infrared (FTIR) spectrometer source for polarized reflectance measurements from 1 um to 20 um wavelength at angles of incidence from 10° to 80°, with an incident beam geometry of
Paul A. Williams, William C. Swann, Nathan R. Newbury
We present theoretical predictions and experimental measurements for the achievable phase noise, timing jitter, and frequency stability in the coherent transport of an optical frequency over a fiber-optic link. Both technical and fundamental limitations to
Nathan R. Newbury, Ian R. Coddington, William C. Swann
Coherent, broadband fiber lasers produce pulse trains with <1 femtosecond relative timing uncertainty and <1 mHz relative frequency uncertainty. These sources can advance many applications including optical frequency metrology, ranging LIDAR, and broadband
Vivek M. Prabhu, Jihoon Kang, Nayool Shin, Do Y. Yoon, Do Y. Jang
A comprehensive structural and electrical characterization of solution-processed blend films of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and poly(alpha-methylstyrene) (PaMS) was performed to understand and optimize the blend
Nathan R. Newbury, Paul A. Williams, William C. Swann
We have recently demonstrated the coherent transfer of an optical signal over a 251 km link of optical fiber using the standard Doppler-cancellation approach to remove the effects of the fiber-link noise. The fundamental limit to the frequency instability
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
Paul A. Williams, William C. Swann, Nathan R. Newbury
We present theory and experiment quantifying the limitations to stable transport of optical frequencies over optical fiber. These are fundamental fiber noise, propagation delay, bidirectional propagation and system noise in the measurement interferometers.
Lu Deng, Edward W. Hagley, Kaijun Jiang, Marvin G. Payne
Using a full density matrix formalism we show that for a lifetime broadened four-level scheme with a signal wave gain medium a large nonlinear phase shift can be induced without signal wave slowdown and attenuation. In this system the signal wave acquires
H G. Schwefel, W Kohler, Z Lu, Jingyun Fan, L Wang
We report a precise direct measurement of the Goos-Hanchen (GH) shift after one reflection off a dielectric interface coated with periodic metal stripes. The spacial displacement of the shift is determined by image analysis. A maximal absolute shift of 5
Uwe Arp, Kun Hou, Ronald Outlaw, Wang Sigen, Mingyao Zhu, Ronald Quinlan, Dennis Manos, Martin Kordesch, Brian Holloway
Carbon nanosheets, a two-dimensional carbon nanostructure, are promising electron cathode materials for applications in vacuum microelectronic devices. This letter demonstrates a simple approach to improve the spatial emission uniformity of carbon
The only way to ensure accurate measurements of optical fiber power is to have your OFPM calibrated in the configuration that you intend to use it. Users must consider the fiber connectors and adapters that they will use as well as the optical wavelength