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Search Publications by John T. Woodward IV

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Displaying 1 - 25 of 53

SI-Traceable Calibrations of Celestial Objects

Keith R. Lykke, Claire E. Cramer, John T. Woodward IV
Photometric calibration is currently the leading source of systematic uncertainty in supernova surveys that aim to determine the nature of dark energy. The bulk

A novel apparatus to measure reflected sunlight from the Moon

Claire E. Cramer, Gerald T. Fraser, Keith R. Lykke, John T. Woodward IV, Alan W. Smith
We describe a new apparatus for measuring the spectral irradiance of the Moon at visible wavelengths. Our effort builds upon the United States Geological Survey

New Instruments to Calibrate Atmospheric Transmission

Claire E. Cramer, Keith R. Lykke, John T. Woodward IV, Peter Zimmer, John T. McGraw, Daniel C. Zirzow
Changing atmospheric transmission accounts for the largest systematic errors limiting photometric measurement precision and accuracy for ground-based telescopes

Ground-based observatory operations optimized and enhanced by direct atmospheric measurements

John T. McGraw, Peter C. Zimmer, Azzam Mansour, Dean C. Hines, Anthony B. Hull, Lisa Rossmann, Daniel C. Zirzow, Steven W. Brown, Gerald T. Fraser, Keith R. Lykke, Allan W. Smith, John T. Woodward IV, Christopher W. Stubbs
Earth’s atmosphere represents a turbulent, turbid refractive element for every ground-based telescope. We describe the significantly enhanced and optimized

Space-based photometric precision from ground-based telescopes

Peter C. Zimmer, John T. McGraw, Anthony B. Hull, Daniel C. Zirzow, Steven W. Brown, Claire E. Cramer, Gerald T. Fraser, Keith R. Lykke, Allan W. Smith, John T. Woodward IV, Christopher W. Stubbs, Mark R. Ackermann, Dean C. Hines
Ground-based telescopes supported by lidar and spectrophotometric auxiliary instrumentation can attain space-based precision for all-sky photometry, with

Internal quantum efficiency modeling of silicon photodiodes

Thomas R. Gentile, Steven W. Brown, Keith R. Lykke, Ping-Shine Shaw, John T. Woodward IV
Results are presented for modeling of the internal quantum efficiency (IQE) of silicon photodiodes in the 400 nm to 900 nm wavelength range. The IQE data are

Hyperspectral Imager Characterization and Calibration

John T. Woodward IV, Steven W. Brown, Allan W. Smith, Keith R. Lykke
Current radiometric calibration standards, specifically blackbody and lamp-based optical radiation sources, produce spatially, spectrally, and temporally simple

Supercontinuum Sources for Metrology

John T. Woodward IV, Allan W. Smith, Colleen A. Jenkins, Chungsan Lin, Steven W. Brown, Keith R. Lykke
Supercontinuum (SC) sources are novel laser-based sources that generate a broad, white-light continuum in single mode photonic crystal fibers. Currently, up to

Characterization of the Latent Image to Developed Image in Model EUV Photoresists

John T. Woodward IV, Kwang-Woo Choi, Vivek M. Prabhu, Shuhui Kang, Kristopher Lavery, Wen-Li Wu, Michael Leeson, Anuja De Silva, Nelson Felix, Christopher K. Ober
Current extreme ultraviolet (EUV) photoresist materials do not yet meet exposure-dose sensitivity, line-width roughness, and resolution requirements. In order

Component Segregation in Model Chemically Amplified Resists

John T. Woodward IV, Theodore Fedynyshyn, David Astolfi, Susan Cann, Michael Leeson
We have applied chemical force microscopy (CFM) to probe the chemical segregation of resist materials. CFM is capable of providing simultaneous information