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Search Publications by: Mark-Alexander Henn (Assoc)

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Displaying 1 - 25 of 27

Harmonic dependence of thermal magnetic particle imaging

September 22, 2023
Author(s)
Thinh Bui, Mark-Alexander Henn, Weston L. Tew, Megan Catterton, Solomon I. Woods
Advances in instrumentation and tracer materials are still required to enable sensitive and accurate 3D temperature monitoring by magnetic particle imaging. We have developed a magnetic particle imaging instrument to observe temperature variations using

Investigating the Harmonic Dependence of MPI Resolution

March 19, 2023
Author(s)
Mark-Alexander Henn, Thinh Bui, Solomon I. Woods
In this work we investigate how the MPI resolution changes as a function of signal harmonics. Based on a simulation study that models a lock-in measurement of the point spread function we apply our findings to actual measurement data obtained from NIST's

Investigating the Influence of Sampling Frequency on X-Space MPI Image Reconstructions

March 19, 2023
Author(s)
Mark-Alexander Henn, Klaus Natorf Quelhas, Solomon I. Woods
In this presentation we employ a direct X-space deconvolution to estimate particle distributions from MPI data. We report on how the accuracy of those estimations changes as a function of sampling frequency and compare the findings to the MPI core operator

Parallel MPI image reconstructions in GPU using CUDA

March 19, 2023
Author(s)
Klaus Natorf Quelhas, Mark-Alexander Henn, Ricardo Cordeiro de Farias, Weston L. Tew, Solomon I. Woods
This work shows that it is possible to obtain faster MPI image reconstructions by implementing the algorithms in parallel in Graphics Processing Units (GPUs) using NVIDIA's CUDA (Compute Unified Device Architecture). While the parallel Kaczmarz's algorithm

Flexible Software for Rigorous Simulations of Magnetic Particle Imaging Systems

March 21, 2022
Author(s)
Klaus Natorf Quelhas, Mark-Alexander Henn, Thinh Bui, Hunter Wages, Weston L. Tew, Solomon I. Woods
Modeling of Magnetic Particle Imaging (MPI) systems allows for developing and testing novel methods for image reconstruction and simulating various setups without the need of real-life measurement data. Here we describe the the initial development of a C++

Uncertainty estimation for 2D magnetic particle imaging

March 21, 2022
Author(s)
Mark-Alexander Henn, Klaus Natorf Quelhas, Solomon I. Woods
Magnetic Particle Imaging (MPI) has in recent years been established as a powerful imaging tool that measures thenon-linear magnetic response of magnetic particles to an applied field. Obtaining quantitative information fromthese images in the form of a

Appraising the extensibility of optics-based metrology for emerging materials

October 4, 2019
Author(s)
Bryan M. Barnes, Mark-Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
To advance computational capabilities beyond conventional scaling limitations, novel device architectures enabled by emerging materials may be required. Optics-based methodologies, central to modern-day process control, will be pursued by the

Data-driven approaches to optical patterned defect detection

September 5, 2019
Author(s)
Mark-Alexander Henn, Hui Zhou, Bryan M. Barnes
Computer vision and classification methods have become increasingly popular in recent years due to ever-increasing computation power. While advances in semiconductor devices are the basis for this growth, few publications have probed the benefits of data

Assessing form-dependent optical scattering at vacuum- and extreme-ultraviolet wavelengths off nanostructures with two-dimensional periodicity

June 24, 2019
Author(s)
Bryan M. Barnes, Mark Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
Several metamaterials and nanostructures are form birefringent, exhibiting effective refractive index differences for orthogonal polarizations due to the placement of subwavelength features if the periodicity is smaller than the incident wavelength. As the

Evaluating the Effects of Modeling Errors for Isolated Finite 3-D Targets

October 19, 2017
Author(s)
Mark Alexander Henn, Bryan M. Barnes, Hui Zhou
Optical 3-D nanostructure metrology utilizes a model-based metrology approach to determine critical dimensions (CDs) that are well below the inspection wavelength. Our project at the National Institute of Standards and Technology is evaluating how to

Combining model-based measurement results of critical dimensions from multiple tools

April 7, 2017
Author(s)
Nien F. Zhang, Bryan M. Barnes, Hui Zhou, Mark Alexander Henn, Richard M. Silver
Model-based measurement techniques use experimental data and simulations of the underlying physics to extract quantitative estimates of the measurands of a specimen based upon a parametric model of that specimen. The uncertainties of these estimates are

Assessing the wavelength extensibility of optical patterned defect inspection

March 29, 2017
Author(s)
Bryan Barnes, Hui Zhou, Mark-Alexander Henn, Martin Sohn, Richard M. Silver
Qualitative comparisons have been made in the literature between the scattering off deep- subwavelength-sized defects and the scattering off spheres in free space to illustrate the challenges of optical defect inspection with decreasing patterning sizes

Evaluating the Effects of Modeling Errors for Isolated Finite3-D Targets

March 29, 2017
Author(s)
Mark-Alexander Henn, Bryan Barnes, Hui Zhou
Optical 3-D nanostructure metrology utilizes a model-based metrology approach to determine critical dimensions (CDs) that are well below the inspection wavelength. Our project at the National Institute of Standards and Technology is evaluating how to

A Library to Enable the Modeling of Optical Imaging of Finite Multi-Line Arrays.

September 30, 2016
Author(s)
Mark Alexander Henn, Bryan M. Barnes
The dataset contains several MATLAB files and input files for the software package JCMsuite that enable the modeling of optical imaging of finite multi-line arrays. (Certain commercial materials are identified in order to specify the experimental procedure

Optimizing Subfield Targets for Nanoscale Quantitative Optical Imaging

September 29, 2016
Author(s)
Mark Alexander Henn, Bryan M. Barnes, Hui Zhou, Martin Y. Sohn, Richard M. Silver
The full 3-D scattered field above finite sets of features has been shown to contain a continuum of spatial frequency information, and with novel optical microscopy techniques and electromagnetic modeling, deep-subwavelength geometrical parameters can be

Enabling Quantitative Optical Imaging for In-die-capable Critical Dimension Targets

April 4, 2016
Author(s)
Bryan M. Barnes, Mark Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
Dimensional scaling trends will eventually bring the semiconductor critical dimensions (CDs) down to only a few atoms in width. New optical techniques are required to address intra-die variability for these CDs using sufficiently small in-die metrology

Optimizing Hybrid Metrology: Rigorous Implementation of Bayesian and Combined Regression.

November 12, 2015
Author(s)
Mark Alexander Henn, Richard M. Silver, John S. Villarrubia, Nien F. Zhang, Hui Zhou, Bryan M. Barnes, Andras Vladar, Bin Ming
Hybrid metrology, e.g. the combination of several measurement techniques to determine critical dimensions, is an important approach to meet the needs of semiconductor industry. A proper use of hybrid metrology may not only yield more reliable estimates for

Deep-subwavelength Nanometric Image Reconstruction using Fourier Domain Optical Normalization

November 5, 2015
Author(s)
Jing Qin, Richard M. Silver, Bryan M. Barnes, Hui Zhou, Ronald G. Dixson, Mark Alexander Henn
Quantitative optical measurements of deep sub-wavelength, three-dimensional, nanometric structures with sensitivity to sub-nanometer details address an ubiquitous measurement challenge. A Fourier domain normalization approach is used in the Fourier optical