A5033806725- Optical Coatings and Gratings
- Advanced X-ray Imaging Techniques
- Astrophysical Phenomena and Observations
- Photonic and Optical Devices
- Advanced Measurement and Metrology Techniques
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Crystallography and Radiation Phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced MEMS and NEMS Technologies
- Advanced Surface Polishing Techniques
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- Semiconductor Lasers and Optical Devices
- Plasma Diagnostics and Applications
- Astro and Planetary Science
- Climate change and permafrost
- Fluid Dynamics and Turbulent Flows
- Spacecraft and Cryogenic Technologies
- Geomagnetism and Paleomagnetism Studies
- Nanowire Synthesis and Applications
- Planetary Science and Exploration
- Heat Transfer Mechanisms
- Aerodynamics and Acoustics in Jet Flows
- Energy Harvesting in Wireless Networks
Marshall Space Flight Center
2022
Massachusetts Institute of Technology
2009-2019
Kavli Institute for Particle Astrophysics and Cosmology
2013
Dartmouth College
2007
Accurate fabrication of high-aspect ratio (HAR) structures in applications from semiconductor devices to x-ray observatories is essential for their optimal performance because directly depends on structure. High-efficiency critical-angle transmission (CAT) gratings enable high-resolution spectroscopy astrophysics, but only ideal when certain performance-critical parameters, like the bar tilts introduced during deep reactive-ion etching, are tuned precise values. Traditional measurement...
The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket experiment launched on July 30, 2021 from the White Sands Missile Range in New Mexico. MaGIXS is a unique solar observing telescope developed to capture spectral images, 6 - 24 Angstrom wavelength range, of coronal active regions. Its novel design takes advantage recent technological advances related fabricating and optimizing optical systems as well breakthroughs inversion methodologies necessary create spectrally...
High-resolution spectroscopy of astrophysical sources is the key to gaining a quantitative understanding history, dynamics, and current conditions cosmos. A large-area (> 1,000 cm<sup>2</sup>), high resolving power (R = λ/Δλ> 3000) soft x-ray grating spectrometer (XGS) that covers lines C, N, O, Ne Fe ions ideal tool address number high-priority science questions from 2010 Decadal Survey, such as connection between super-massive black holes large-scale structure via...
Accurate predictions of harmful space weather effects are mandatory for the protection astronauts and other assets in space, whether Earth or lunar orbit, transit between solar system objects, on surface planetary bodies. Because corona is multithermal (i.e., structured not only but also temperature), wavelength-separated data provide crucial information that available to imaging methods integrate over temperature. The extreme ultraviolet (EUV) wavelengths enable us focus directly high...
Abstract Arcus is a proposed Explorer Class soft X-ray grating spectrometer. It aims to explore cosmic feedback by mapping hot gases within and between galaxies galaxy clusters characterizing jets winds from supermassive black holes investigate the dynamics of protoplanetary disks stellar accretion. features 12 m focal-length grazing-incidence silicon pore optics (SPO) developed for Athena mission. Critical-angle transmission (CAT) gratings efficiently disperse high diffraction orders onto...
The authors present a breakthrough multistage dry-etch process to create 100 nm half-pitch gratings in silicon with depths up 6 μm. Interference lithography was used pattern an optically matched stack of materials form 400-nm-thick oxide hard-mask. then mask the subsequent deep reactive-ion etching silicon. In this article, describe their grating patterning, transfer, and etch processes, progress toward combining technique coarser scale steps designed integrated mechanical support structure...
A fully integrated fabrication process has been developed to fabricate freestanding, ultrahigh aspect ratio silicon gratings with potassium hydroxide (KOH)-polished sidewalls. The are being for wavelength-dispersive, soft x-ray spectroscopy on future space telescopes. For this application, the grating needs have a large open-area fraction and smooth sidewalls (roughness &lt; 1 nm) maximize efficiency. prototype fabricated presented here tested synchrotron beamline demonstrated an...
The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a sounding rocket instrument that flew on July 30, 2021 from the White Sands Missile Range, NM. was designed to address specific science questions require differential emission measures of solar soft spectrum 6 – 25[Formula: see text]Å(0.5 2.1[Formula: text]keV). MaGIXS comprises Wolter-I telescope, slit-jaw imaging system, an identical pair grazing incidence paraboloid mirrors, planar grating and CCD camera. While implementing...
Soft x-ray spectroscopy with high resolving power (R = λ/Δλ) and large effective area (A) addresses numerous unanswered science questions about the physical laws that lead to structure of our universe. In soft band R > 1000 can currently only be achieved diffraction grating-based spectroscopy. Criticalangle transmission (CAT) gratings combine advantages blazed reflection (high efficiency, use higher orders) those conventional (relaxed alignment tolerances temperature...
A fabrication process has been developed to chemically polish the sidewalls of 200 nm-pitch gratings via potassium hydroxide (KOH) etching following Bosch deep reactive-ion (DRIE) process. Previous KOH polishing experiments focused on micron scale features. This work is first reported combined DRIE-KOH nanoscale for ultrahigh aspect ratio structures with feature sizes 30 times smaller than previously published work. The primary application x-ray spectroscopy and requires polished efficient...
A nanofabrication process has been developed for a novel critical-angle transmission grating astronomical x-ray spectroscopy. The pitch of the gratings is 200 nm and depth 4 μm, which exceeds state-of-the-art in aspect ratio by over factor 2 ultrahigh freestanding nanoscale with open areas on order 50% spanning several square centimeters. They have broad array other applications, including neutral mass spectroscopy, ultraviolet filtration, phase contrast imaging are fabricated as monolithic...
We present measurements of the resolving power a soft x-ray spectrometer consisting 200 nm-period lightweight, alignment-insensitive critical-angle transmission (CAT) gratings and lightweight slumped-glass Wolter-I focusing mirror pair. measure model contributions from source, mirrors, detector pixel size, grating period variation to natural line width spectrum Al Mg K$_{\alpha_1 \alpha_2}$ doublets. Measuring up 18$^{\rm th}$ diffraction order at characteristic Al-K wavelengths we...
The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a NASA sounding rocket instrument designed to obtain spatially resolved soft spectra of the solar atmosphere in 6–24 Å (0.5–2.0 keV) range. consists single shell Wolter Type-I telescope, slit, and spectrometer comprising matched pair grazing incidence parabolic mirrors planar varied-line space diffraction grating. achieve 50 mÅ spectral resolution 5 arcsecond spatial along ±4-arcminute long launch planned for 2019. We report on...
We report progress toward developing a scanning laser reflection (LR) tool for alignment and period measurement of critical-angle transmission (CAT) gratings. It operates on similar principle as built in 1994 which characterized variations grating facets the Chandra X-ray Observatory. A specularly reflected beam first-order diffracted were used to record local variations, surface slope line orientation. In this work, normal-incidence was added measure (instead angled-incidence beam). Since...
Arcus is a high-resolution soft x-ray spectroscopy mid-size Explorer mission selected for NASA Phase A concept study. It designed to explore structure formation through measurements of hot baryon distributions, feedback from black holes, and the evolution stars, disks, exoplanet atmospheres. The design provides unprecedented sensitivity in 1.2-5 nm wavelength band with effective area up 350 cm<sup>2</sup> spectral resolving power R > 2500. technology based on highly modular that features...
A number of high priority subjects in astrophysics can be addressed by a state-of-the-art soft x-ray grating spectrometer, such as the role Active Galactic Nuclei galaxy and star formation, characterization Warm-Hot Intergalactic Medium missing baryon problem, halos around Milky Way nearby galaxies, well stellar coronae surrounding winds disks. An Explorer-scale, largearea (> 1,000 cm<sup>2</sup>), resolving power (<i>R</i> =λ/Δλ > 3,000) spectrometer is highly...
In response to Astro2020 recommendations, NASA has issued an announcement of opportunity for astrophysics probe explorer. Arcus-Probe is a mission concept featuring two co-aligned high-resolution spectrometers, one the soft x-ray band, and far ultraviolet. This combination instruments will provide unprecedented performance exploration feedback that shapes structure influences dynamics our universe across many scales, ranging from galaxy clusters down individual stars. band spectrometer...
We report several break-through nanofabrication developments enabling high efficiency and resolving power spectrometers in the soft x-ray band. The device is critical-angle transmission (CAT) grating, which combines low mass relaxed alignment tolerances of a grating with broad-band diffraction orders blazed reflection grating. Past work successfully demonstrated CAT concept; however, open-area fraction was often less than 20% whilst more 50% desired. This presents numerous challenges...
High resolution absorption and emission line spectroscopy in the soft x-ray band are promising techniques to measure hot baryon distributions extended galaxy halos, clusters, connecting filaments of cosmic web. It can characterize outflows from supermassive black holes help understand their impact on structure evolution interstellar medium beyond. Stellar magnetic activity, accretion, coronal flares additional targets for spectroscopy. Higher resolving power larger effective area than those...
The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a NASA sounding rocket instrument that designed to observe soft emissions from 24 - 6.0 Å (0.5 2.0 keV energies) in the solar atmosphere. For first time, high-temperature, low-emission plasma will be observed directly with 5 arcsecond spatial resolution and 22 mÅ spectral resolution. unique optical design consists of Wolter I telescope 3-optic grazing- incidence spectrometer. spectrometer utilizes finite conjugate mirror pair...
The authors report the development of fast, nondestructive, and high accuracy metrology for characterization profile tilt relative to surface normal in nanoscale gratings using x-ray diffraction. Gratings were illuminated with a collimated beam (Cu Kα), similar variable-angle small-angle scattering, record changes diffraction efficiency (DE) as function incidence angle. Simulations scalar theory rigorous coupled wave analysis predict extrema (0th order DE minimized, ±1st maximized) when...
Arcus, a mission proposed as Medium Size Explorer for high-resolution x-ray spectroscopy, requires unprecedented sensitivities: high resolving power (λ/Δλ >; 2500) and large collecting area (~ 350 cm<sup>2</sup>). The core instruments on Arcus are Critical-Angle Transmission (CAT) grating spectrometers consisting of hundreds co-aligned diffraction gratings. gratings require thorough quality control along the entire manufacturing process: from bare silicon wafers to CAT...