Dr. David W. Blodgett Profile

Dr. David W. Blodgett

Scientist at Johns Hopkins Univ Applied Physics Lab LLC

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Author

Publications (22)

Proceedings Article | 5 March 2021 Presentation + Paper

Evaluation of neural information content from the phase component of a 32-channel frequency-domain fNIRS system

Clara Scholl, Jeremiah Wathen, Michael Fitch, Griffin Milsap, Margaret Thompson, Marisel Villafañe-Delgado, Kachi Odoemene, Adam Eggebrecht, Zachary Markow, Edward Richter, Jason Trobaugh, Joseph Culver, David Blodgett, Scott Hendrickson

Proceedings Volume 11629, 116292H (2021) https://doi.org/10.1117/12.2581851

KEYWORDS: Tissues, Principal component analysis, Human subjects, Head, Avalanche photodiodes

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Proceedings Article | 5 March 2021 Presentation + Paper

A 32-channel frequency-domain fNIRS system based on silicon photomultiplier receivers

Jeremiah Wathen, Michael Fitch, Vincent Pagán, Griffin Milsap, Emil McDowell, Lafe Spietz, Zachary Markow, Jason Trobaugh, Edward Richter, Adam Eggebrecht, Joseph Culver, David Blodgett, Scott Hendrickson

Proceedings Volume 11629, 116291P (2021) https://doi.org/10.1117/12.2581482

KEYWORDS: Receivers, Silicon photomultipliers, Transmitters, Transformers, Silicon, Semiconductors, Nanolithography, Modulation, Image resolution, Fiber couplers

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Proceedings Article | 9 March 2020 Presentation

In-vivo imaging of neurological signatures using coherent optical techniques (Conference Presentation)

David Blodgett, Carissa Rodriguez, Eyal Bar-Kochba, Clara Scholl, Nicole Steiner, Austen Lefebvre, Marek Mirski

Proceedings Volume 11226, 112260S (2020) https://doi.org/10.1117/12.2548582

KEYWORDS: Tissue optics, In vivo imaging, Near infrared, Signal detection, Imaging systems, Neuroimaging, Optical properties, Absorption, Motion models, Tissues

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Proceedings Article | 8 May 2018 Paper

Brain imaging for neural tissue health assessment

David Blodgett, Eyal Bar-Kochba, Aaron Criss, Tom Criss, Jason Harper, Grace Hwang, Clare Lau, Carissa Rodriguez, Carlos Renjifo, Clara Scholl, Austen Lefebvre, Marek Mirski

Proceedings Volume 10639, 106391G (2018) https://doi.org/10.1117/12.2305789

KEYWORDS: Tissue optics, Imaging systems, Digital holography, Tissues, Holograms, Spatial resolution, Neuroimaging, Image processing

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Proceedings Article | 18 May 2017 Presentation + Paper

Portable non-invasive brain-computer interface: challenges and opportunities of optical modalities

Clara Scholl, Scott Hendrickson, Bruce Swett, Michael Fitch, Erich Walter, Michael McLoughlin, Mark Chevillet, David Blodgett, Grace Hwang

Proceedings Volume 10194, 101941K (2017) https://doi.org/10.1117/12.2262844

KEYWORDS: Human-machine interfaces, Tissue optics, Brain, Human-computer interaction, Optical sensors, Temporal resolution, Coherent optics, Spatial resolution, Brain-machine interfaces, Neurons, Tissues, Signal processing, Functional magnetic resonance imaging, Scattering

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Proceedings Article | 18 May 2005 Paper

Optical characterization of AlON and spinel

D. Blodgett, D. Hahn, M. Thomas

Proceedings Volume 5786, (2005) https://doi.org/10.1117/12.608985

KEYWORDS: Bidirectional reflectance transmission function, Absorption, Transmittance, Spinel, Mid-IR, Sensors, Sapphire, Optical properties, Temperature metrology, Polishing

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Proceedings Article | 14 November 2003 Paper

Analysis and representation of BSDF and BRDF measurements

Michael Thomas, David Blodgett, Daniel Hahn

Proceedings Volume 5192, (2003) https://doi.org/10.1117/12.508560

KEYWORDS: Bidirectional reflectance transmission function, Data modeling, Sensors, Reflectivity, Reflection, Solids, Opacity, Optical fibers, Integration, Signal detection

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Proceedings Article | 26 September 2003 Paper

Longwave infrared absorption properties of ZnS and ZnSe

David Blodgett, Michael Thomas, Daniel Hahn, Simon Kaplan

Proceedings Volume 5078, (2003) https://doi.org/10.1117/12.487874

KEYWORDS: Zinc, Absorption, Infrared radiation, Transmittance, Data modeling, Solids, Long wavelength infrared, Spectroscopy, Temperature metrology, Thermal modeling

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Proceedings Article | 26 September 2003 Paper

Characterization and modeling of the infrared properties of diamond and SiC

Daniel Hahn, Michael Thomas, David Blodgett, Simon Kaplan

Proceedings Volume 5078, (2003) https://doi.org/10.1117/12.487875

KEYWORDS: Diamond, Absorption, Silicon carbide, Chemical vapor deposition, Data modeling, Transmittance, Infrared radiation, Temperature metrology, Thermal modeling, Infrared materials

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Proceedings Article | 26 September 2003 Paper

Characterization and modeling of the infrared properties of GaP and GaAs

Michael Thomas, David Blodgett, Daniel Hahn, Simon Kaplan

Proceedings Volume 5078, (2003) https://doi.org/10.1117/12.487878

KEYWORDS: Absorption, Gallium arsenide, Transmittance, Data modeling, Temperature metrology, Infrared radiation, Spectroscopy, Thermal modeling, Sensors, Solids

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Proceedings Article | 27 August 2003 Paper

Dental hard tissue characterization using laser-based ultrasonics

David Blodgett, Ward Massey

Proceedings Volume 4961, (2003) https://doi.org/10.1117/12.488445

KEYWORDS: Teeth, Dental caries, Ultrasonics, Acoustics, Wave propagation, Natural surfaces, Pulsed laser operation, Absorption, Aluminum, Ultrasonography

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Proceedings Article | 18 August 2003 Paper

Detection of rebar delamination using modal analysis

David Blodgett

Proceedings Volume 5057, (2003) https://doi.org/10.1117/12.482718

KEYWORDS: Bridges, Corrosion, Modal analysis, Acoustics, Nondestructive evaluation, Signal processing, Applied physics, Visualization, Inspection, Resistance

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Proceedings Article | 27 June 2002 Paper

Ultrasonic assessment of tooth structure

David Blodgett

Proceedings Volume 4617, (2002) https://doi.org/10.1117/12.472536

KEYWORDS: Teeth, Acoustics, Ultrasonics, Ultrasonography, Transducers, Pulsed laser operation, Reflection, Wave propagation, Cements, Nondestructive evaluation

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Proceedings Article | 5 December 2001 Paper

Sub-micron elastic property characterization of materials using a near-field scanning optical microscope

David Blodgett, James Spicer

Proceedings Volume 4456, (2001) https://doi.org/10.1117/12.449527

KEYWORDS: Ultrasonics, Near field, Ultrasonography, Near field optics, Transducers, Near field scanning optical microscopy, Spatial resolution, Copper, Wave propagation, Microscopes

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The ability to characterize the sub-surface mechanical properties of a bulk or thin film material at the sub-micron level has applications in the microelectronics and thin film industries. In the microelectronics industry, with the decrease of line widths and the increase of component densities, sub-surface voids have become increasingly detrimental. Any voids along an integrated circuit (IC) line can lead to improper electrical connections between components and can cause failure of the device. In the thin film industry, the detection of impurities is also important. Any impurities can detract from the film's desired optical, electrical, or mechanical properties. Just as important as the detection of voids and impurities, is the measurement of the elastic properties of a material on the nanometer scale. These elastic measurements provide insight into the microstructural properties of the material. We have been investigating a technique that couples the high-resolution surface imaging capabilities of the apertureless near-field scanning optical microscope (ANSOM) with the sub-surface characterization strengths of high-frequency ultrasound. As an ultrasonic wave propagates, the amplitude decreases due to geometrical spreading, attenuation from absorption, and scattering from discontinuities. Measurement of wave speeds and attenuation provides the information needed to quantify the bulk or surface properties of a material. The arrival of an ultrasonic wave at or along the surface of a material is accompanied with a small surface displacement. Conventional methods for the ultrasound detection rely on either a contact transducer or optical technique (interferometric, beam deflection, etc.). However, each of these methods is limited by the spatial resolution dictated by the detection footprint. As the footprint size increases, variations across the ultrasonic wavefront are effectively averaged, masking the presence of any nanometer-scale sub-surface or surface mechanical property variations. The use of an ANSOM for sensing ultrasonic wave arrivals reduces the detection footprint allowing any nanometer scale variations in the microstructure of a material to be detected. In an ANSOM, the ultrasonic displacement is manifested as perturbations on the near-field signal due to the small variations in the tip-sample caused by the wave arrival. Due to the linear dependence of the near-field signal on tip-sample separation, these perturbations can be interpreted using methods identical to those for conventional ultrasonic techniques. In this paper, we report results using both contact transducer (5 MHz) and laser-generated ultrasound.

Proceedings Article | 7 September 2001 Paper

Compressive strengthening of sapphire by neutron irradiation

Thomas Regan, Daniel Harris, Rhonda Stroud, John White, David Blodgett, Kevin Baldwin, Joseph Miragliotta, Michael Thomas, Milton Linevsky, John Giles, Thomas Kennedy, Mohammad Fatemi, David Black, K. Peter Lagerloef

Proceedings Volume 4375, (2001) https://doi.org/10.1117/12.439191

KEYWORDS: Sapphire, Absorption, Annealing, Crystals, Cadmium, Aluminum, Infrared radiation, X-ray diffraction, Gamma radiation, Spectroscopy

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Proceedings Article | 7 September 2001 Paper

Measurement of absorption and scattering properties of CVD diamond

Michael Thomas, William Green, Di Yang, David Blodgett

Proceedings Volume 4375, (2001) https://doi.org/10.1117/12.439178

KEYWORDS: Diamond, Temperature metrology, Chemical vapor deposition, Transmittance, Absorption, Mass attenuation coefficient, Scattering, Scatter measurement, Light scattering, Optical testing

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Proceedings Article | 7 September 2001 Paper

Measurement of the temperature-dependent refractive index and relative photoelastic constant of zinc sulfide

David Blodgett, Di Yang, Suzanne Walts, Michael Thomas

Proceedings Volume 4375, (2001) https://doi.org/10.1117/12.439179

KEYWORDS: Refractive index, Zinc, Temperature metrology, Photoelasticity, Thermal optics, Fringe analysis, Data modeling, Sensors, Silicon, Polarizers

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Proceedings Article | 9 July 2001 Paper

Optical BRDF and BSDF measurements of human incisors from visible to mid-infrared wavelengths

David Blodgett, S. Webb

Proceedings Volume 4257, (2001) https://doi.org/10.1117/12.434733

KEYWORDS: Bidirectional reflectance transmission function, Teeth, Absorption, Scattering, Tissue optics, Light scattering, Tissues, Crystals, Sensors, Light wave propagation

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Proceedings Article | 13 June 2000 Paper

Laser ultrasonic techniques for assessment of tooth structure

David Blodgett, Kevin Baldwin

Proceedings Volume 3914, (2000) https://doi.org/10.1117/12.388083

KEYWORDS: Teeth, Ultrasonics, Acoustics, Ultrasonography, Interferometers, Transducers, Absorption, Pulsed laser operation, Interfaces, Nd:YAG lasers

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Proceedings Article | 26 July 1999 Paper

High-temperature mechanical characterization of single-crystal sapphire using laser-based ultrasonics

David Blodgett, Kevin Baldwin

Proceedings Volume 3705, (1999) https://doi.org/10.1117/12.354641

KEYWORDS: Ultrasonics, Sapphire, Wave propagation, Ultrasonography, Interferometers, Crystals, Carbon dioxide lasers, Sapphire lasers, Acoustics, Absorption

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Proceedings Article | 15 June 1994 Paper

Improved vanadium-dioxide-based infrared spatial light modulator

David Blodgett, Michael Elko, Philip McNally

Proceedings Volume 2223, (1994) https://doi.org/10.1117/12.177949

KEYWORDS: Spatial light modulators, Diodes, Infrared radiation, Reflectivity, Vanadium, Semiconductors, Chemical vapor deposition, Diamond, Switching

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Proceedings Article | 31 August 1993 Paper

Vanadium-dioxide-based infrared spatial light modulators

David Blodgett, Charles Lange, Philip McNally

Proceedings Volume 1969, (1993) https://doi.org/10.1117/12.154728

KEYWORDS: Diodes, Spatial light modulators, Thermoelectric materials, Reflectivity, Silicon, Thin films, Epoxies, Thermal analysis, Switching, Infrared radiation

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Showing 5 of 22 publications

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