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Search Publications by: Yuqin Zong (Fed)

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Displaying 1 - 25 of 99

Influence of Spectral Bandwidth on the Working Curve in Vat Photopolymerization

April 29, 2024
Author(s)
Benjamin Caplins, Thomas Kolibaba, Uwe Arp, C Cameron Miller, Yuqin Zong, Dianne L. Poster, Callie Higgins, Jason Killgore
In vat photopolymerization, 3-dimensional parts are fabricated by using patterned light to spatially cure a liquid resin. One of the foundational measurements for vat photopolymerization is known as the working curve whereby the depth (i.e. thickness) of

Results of an Interlaboratory Study on the Working Curve in Vat Photopolymerization

March 18, 2024
Author(s)
Thomas Kolibaba, Jason Killgore, Benjamin Caplins, Callie Higgins, Uwe Arp, C Cameron Miller, Yuqin Zong, Dianne L. Poster
The working curve informs resin properties and print parameters for stereolithography, digital light processing, and other photopolymer additive manufacturing (PAM) technologies. First demonstrated in 1992, the working curve measurement of cure depth vs

Impact of fin aspect ratio on enhancement of external quantum efficiency in single AlGaN fin light-emitting diodes pixels

June 26, 2023
Author(s)
Babak Nikoobakht, Yuqin Zong, Okan Koksal, Amit Agrawal, Christopher B. Montgomery, Jacob Leach, Michael Shur
Previously, we showed within a sub-micron fin shape heterojunction, as current density increases, the non-radiative Auger recombination saturates mediated by the extension of the depletion region into the fin, resulting in a droop-free behavior. In this

Characterizing light engine uniformity and its influence on LCD-based vat photopolymerization printing

December 27, 2022
Author(s)
Benjamin Caplins, Callie Higgins, Thomas Kolibaba, Uwe Arp, C Cameron Miller, Dianne L. Poster, Clarence Zarobila, Yuqin Zong, Jason Killgore
Vat photopolymerization (VP) is a rapidly growing category of additive manufacturing. As VP methods mature the expectation is that the quality of printed parts will be highly reproducible. At present, detailed characterization of the light engines used in

NIST Traveling Tunable Laser Projector (TTLP) for UV-Blue Disinfection Dose Determinations

June 21, 2022
Author(s)
Thomas C. Larason, Steven Grantham, Clarence Zarobila, Yuqin Zong, C Cameron Miller, Michael Schuit, Brian Holland, Stewart Wood, Melissa Krause
As COVID-19 was overtaking the world in the spring of 2020, the National Institute of Standards and Technology began collaborating with the National Biodefense Analysis and Countermeasures Center to study the inactivation of SARS-CoV-2 to different UV and

Final report on the CCPR Key Comparison CCPR-K3.2014 Luminous Intensity

June 16, 2022
Author(s)
C Cameron Miller, Yuqin Zong, Arnold Gaertner, Eric Cote, Joaquin Campos, Gael Obein, Peter Blattner, Reto Scafer, Liu Hui, Jiang Xiaomei, Errol Atkinson, Erik Thorvaldson, Kenichi Kinoshita, Rheinhardt Sieberhagen, Irma Rabe, Teresa Goodman, Barry Scott, Armin Sperling, Detlef Lindner, Boris KHlevnoy, Evgeniy Ivashin
The metrological equivalence of national measurement standards in the field of photometry and radiometry is determined by a set of key comparisons chosen and organized by the Consultative Committee of Photometry and Radiometry (CCPR) of the Comité

CALIBRATION OF SPECTRORADIOMETERS USING TUNABLE LASERS

April 22, 2021
Author(s)
Yuqin Zong, Ping-Shine Shaw, Joseph Rice, C Cameron Miller
To shorten the long calibration chain when using the conventional source-based approach and therefore to reduce spectroradiometer's calibration uncertainty, we developed a detector-based approach to calibrate spectroradiometers directly against a transfer

Recent research and development in photometry at NIST

April 22, 2021
Author(s)
Yuqin Zong, Maria Nadal, Benjamin K. Tsai, C Cameron Miller
Many developments were made in recent years in photometry at NIST for reducing measurement uncertainties, increasing calibration efficiencies, and adding measurement capabilities. The 40 years old photometry laboratory has been renovated. The new

STANDARD LEDS WITH SUPERIOR LONG-TERM STABILITY

April 22, 2021
Author(s)
Yuqin Zong, Weiqiang Zhao, C Cameron Miller
A large-chip standard LED with superior long-term stability have been developed at NIST. The standard LED uses a large, specialty die rated for 50 W but is operated under 3 W to eliminate aging effect. The standard LED was seasoned for one year and

High-brightness lasing at submicrometer enabled by droop-free fin light-emitting diodes (LEDs)

August 14, 2020
Author(s)
Robin P. Hansen, Amit K. Agrawal, Michael Shur, Jerry Tersoff, Babak Nikoobakht, Yuqin Zong
"Efficiency droop," i.e., a decline in brightness of light-emitting diodes (LEDs) at high electrical currents, limits the performance of all commercial LEDs and has limited the output power of submicrometer LEDs and lasers to nanowatts. We present a fin p

Invited Article: Advances in Tunable Laser-based Radiometric Calibration Applications at the National Institute of Standards and Technology, USA

September 26, 2018
Author(s)
John T. Woodward IV, Ping-Shine Shaw, Howard Yoon, Yuqin Zong, Steven W. Brown, Keith R. Lykke
Recent developments at the National Institute of Standards and Technology's facility for Spectral Irradiance and Radiance responsivity Calibrations using Uniform Sources (SIRCUS) are presented. The facility is predicated on the use of broadly tunable