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Metrology

Optical/photometry/laser metrology

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Published Date
Displaying 326 - 350 of 383

Detection of circular polarization in light scattered from photosynthetic microbes

May 12, 2009
Author(s)
William Sparks, James H. Hough, Thomas Germer, Feng Chen, Shiladitya DasSarma, Priya DasSarma, Frank Robb, Nadine Manset, Ludmilla Kolokolova, Neill Reid, F. D. Macchetto, William Martin
The identification of a universal biosignature that could be sensed remotely is critical to the prospects for success in the search for life elsewhere in the universe. A candidate universal biosignature is homochirality, which is likely to be a generic

Development of Ultrafast Photochromic Organometallics and Photoinduced Linkage Isomerization of Arene Chromium Carbonyl Derivatives

February 20, 2009
Author(s)
Tung T. To, Edwin J. Heilweil, Duke Charles, Ruddick Kristie, Webster E. Charles, Burkey Theodore
We review recent studies of processes relevant to photoinduced linkage isomerization of organometallic systems with the goal of preparing organometallics with an efficient and ultrafast photochromic response. The organometallic system thus corresponds to

The Marine Optical BuoY (MOBY) Radiometric Calibration and Uncertainty Budget for Ocean Color Satellite Sensor Vicarious Calibration

December 31, 2008
Author(s)
M Feinholz, B. Carol Johnson, Steven W. Brown, S Flora, M Yarbrough, Terrance Houlihan, D Peters, Yong S. Kim, J Mueller, Dennis Clark
For the past decade, the Marine Optical Buoy (MOBY), an autonomous radiometric buoy stationed in the waters off Lanai, Hawaii, has been the primary in-water oceanic observatory for the vicarious calibration of the U. S. satellite ocean color sensors

f1' EVALUATION AND MEASUREMENT COMPARISON

October 1, 2008
Author(s)
Jiangen PAN, Haiping SHEN, Yuqin Zong, Yoshi Ohno
The mismatch of spectral responsivity to the CIE V(lambda) function, i. e., the f1' index, is the most critical characteristic of photometers and tristimulus colorimeters. The f1' value varies with measurement conditions, which is often omitted in the f1'

Derivation of the MODIS Aqua Point-Spread Function for Ocean Color Bands

September 11, 2008
Author(s)
Gerhard Meister, Yuqin Zong, Charles R. McClain
The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Earth Observing System (EOS) Aqua platform has 9 spectral bands with center wavelengths from 412nm to 870nm that are used to produce the standard ocean color data products. Ocean scenes

Dual-CGH Interferometry Test for X-Ray Mirror Mandrels

June 15, 2008
Author(s)
Guangjun Gao, John Lehan, Ulf Griesmann
We describe a glancing-incidence interferometric double-pass test, based on a pair of computer generated holograms (CGHs), for mandrels used to fabricate x-ray mirrors for space-based x-ray telescopes. The design of the test and its realization are

High Accuracy Dual Lens Transmittance Measurements

August 1, 2007
Author(s)
J Cheung, James Gardner, Alan L. Migdall, Sergey Polyakov, Michael Ware
We show how to determine the transmittance of short focal length lenses (f 19 mm, in this case) with an uncertainty of 1 part in 103 or better by measuring transmittances of lens pairs of a set of three or more lenses with the same nominal focal length

Cholesterol/Phospholipid Interactions in Hybrid Bilayer Membranes

May 25, 2007
Author(s)
Dustin Levy, Kimberly Briggman
The interactions between cholesterol and saturated phospholipids in hybrid bilayer membranes (HBMs) were investigated using the interface-sensitive technique of vibrational sum frequency spectroscopy (VSFS). The unique sensitivity of VSFS to order/disorder

Accurate color measurement methods for medical displays

February 15, 2007
Author(s)
Anindita Saha, Hongye Liang, Aldo Badano, Edward F. Kelley
We report on the characterization of two novel probes for measuring display color without contamination from other screen areas or off-normal emissions. The probes are characterized using a scanning slit method and a moving laser and LED arrangement. The

Characterization and Calibration of an Optical Time Domain Reflectometer Calibrator

August 23, 2006
Author(s)
Donald R. Larson, Nicholas Paulter, Kenneth C. Blaney
We report the results of an investigation into the signal characteristics and behavior of an instrument used to calibrate Optical Time Domain Reflectometers. This instrument implements the Telecommunications Industry Association standard TIA/EIA-455-226

Achieving Higher Photon Counting Rates Using Multiplexed Detectors

August 13, 2006
Author(s)
Stefania Castelletto, Ivo P. Degiovanni, Alan L. Migdall, Sergey Polyakov, V Schettini
As the quantum information field advances, the need for improved single-photon devices is becoming more critical. Quantum information systems are often limited by detector deadtime to count rates of a few MHz, at best. We present a multiplexed detection

Optical Metrology for LEDs and Solid State Lighting

February 9, 2006
Author(s)
Yoshi Ohno
The performance of Light Emitting Diodes (LEDs), including efficiency, flux level, lifetime, and the variation of color, is advancing at a remarkable pace. LEDs are increasingly used for many applications including automotive, aviation, display

Terahertz Spectroscopy of Solid Serine and Cysteine

November 10, 2005
Author(s)
Timothy M. Korter, M B. Campbell, M C. Beard, Edwin J. Heilweil
Terahertz (THz) absorption spectra of the amino acids L-serine and L-cysteine in teh solid phase at 77K and 298 K are reported and compared to vibrational spectral results from Density Functional Theory for these species.

Effect of Dissolved Air on the Density and Refractive Index of Water

September 30, 2005
Author(s)
Allan H. Harvey, Simon G. Kaplan, John H. Burnett
We consider the effect of dissolved air on the density and the refractive index of liquid water from 0 ¿aC to 50 ¿aC. The density effect is calculated from the best available values of Henry's constants and partial molar volumes for the components of air

Luminance probes for contrast measurements in medical displays

May 1, 2003
Author(s)
Aldo Badano, Scott Pappada, Edward F. Kelley, Michael J. Flynn, Sandrine Martin, Jerzy Kanicki
We report on a comparative study that examines four conic luminance probes in their ability to measure small-spot display contrast. We performed linear scans of a slit using a computer-controlled stage. We found that, although the probes were assembled
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