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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Purcell-Enhanced Emissions from Diamond Color Centers in Slow Light Photonic Crystal Waveguides

Diamond color centers are promising candidates for optically addressable quantum memories, which motivates the development of efficient photonic interfaces, often using nanophotonic cavities with narrow spectral line widths and small mode volumes. However, they require perfect spectral and spatial overlap between the cavity mode and quantum emitter, which is challenging. This is especially true for solid-state quantum emitters that are often randomly positioned and suffer from inhomogeneous broadening. Another approach to enhance light-matter interaction across large optical bandwidths and areas is using slow light waveguides. Here, in this study, we demonstrate diamond slow light photonic crystal (PhC) waveguides optically coupled to embedded silicon-vacancy (SiV) color centers. We use the recently developed thin-film diamond approach to fabricate fully suspended two-dimensional PhC waveguides. We demonstrate waveguide modes with high group indices up to 70 and observe Purcell-enhanced emissions of the SiVs. Our approach represents a practical diamond platform for robust spin-photon interfaces with color centers.

2D photonic crystal waveguide↗
DOE OSTI2022

Aging of galaxies along the morphological sequence, marked by bulge growth and disk quenching

Aims: We revisit the color bimodality of galaxies using the extensive EFIGI morphological classification of nearby galaxies. Methods: The galaxy profiles from the Sloan Digital Sky Survey (SDSS) gri images were decomposed as a bulge and a disk by controlled profile modeling with the Euclid SourceXtractor++ software. The spectral energy distributions from our resulting gri SDSS photometry complemented with Galaxy Evolution Explorer (GALEX) NUV photometry were fitted with the ZPEG software and PEGASE.2 templates in order to estimate the stellar masses and specific star formation rates (sSFR) of whole galaxies as well as their bulge and disk components. Results: The absolute NUV-r color versus stellar mass diagram shows a continuous relationship between the present sSFR of galaxies and their stellar mass, which spans all morphological types of the Hubble sequence monotonously. Irregular galaxies to intermediate-type Sab spirals make up the “Blue Cloud” across 4 orders of magnitude in stellar mass but a narrow range of sSFR. This mass build-up of spiral galaxies requires major mergers, in agreement with their frequently perturbed isophotes. At high mass, the Blue Cloud leads to the “Green Plain”, dominated by S0a and Sa early-type spirals. It was formerly called the “Green Valley”, due to its low density, but we rename it because of its wide stretch and nearly flat density over ~2 mag in NUV-r color (hence sSFR), despite a limited range of stellar mass (1 order of magnitude). The Green Plain links up the “Red Sequence”, containing all lenticular and elliptical galaxies with a 2 order of magnitude mass interval, and systematically higher masses for the ellipticals. We confirm that the Green Plain cannot be studied using u - r optical colors because it is overlayed by the Red Sequence, hence NUV data are necessary. Galaxies across the Green Plain undergo a marked growth by a factor 2 to 3 in their bulge-to-total mass ratio and a systematic profile change from pseudo to classical bulges, as well as a significant reddening due to star formation fading in their disks. The Green Plain is also characterized by a maximum stellar mass of 10 11.7 M ⊙ beyond which only elliptical galaxies exist, hence supporting the scenario of ellipticals partly forming by major mergers of massive disk galaxies. Conclusions: The EFIGI attributes indicate that dynamical processes (spiral arms and isophote distortions) contribute to the scatter of the Main Sequence of star-forming galaxies (Blue Cloud), via the enhancement of star formation (flocculence, HII regions). The significant bulge growth across the Green Plain confirms that it is a transition region, and excludes a predominantly quick transit due to rapid quenching. The high frequency of bars for all spirals as well as the stronger spiral arms and flocculence in the knee of the Green Plain suggest that internal dynamics, likely triggered by flybys or (mainly minor) mergers, may be the key to the bulge growth of massive disk galaxies, which is a marker of the aging of galaxies from star forming to quiescence. The Hubble sequence can then be considered as an inverse sequence of galaxy physical evolution.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1972

Mars' great storm of 1971.

Description of the development of this planet-wide storm and its subsequent decline through mid-January 1972. The initial core of the disturbance extended northeast to southwest. Preliminary examination of photographic data indicates that the storm, yellow in color, spread completely around the planet in about 16 days. During the storm, red- and green-light photographs recorded Mars as brighter than normal, while in blue it was only slightly brighter, and in the ultraviolet there was no significant change. The history of yellow clouds is discussed. They seem to germinate in specific areas in the southern hemisphere, such as the Hellas-Noachis region. Another yellow cloud is predicted for July or August of 1973.

Capen, C. F.↗
NASA NTRS1973

Analysis of ERTS imagery using special electronic viewing/measuring equipment

An electronic satellite image analysis console (ESIAC) is being employed to process imagery for use by USGS investigators in several different disciplines studying dynamic hydrologic conditions. The ESIAC provides facilities for storing registered image sequences in a magnetic video disc memory for subsequent recall, enhancement, and animated display in monochrome or color. Quantitative measurements of distances, areas, and brightness profiles can be extracted digitally under operator supervision. Initial results are presented for the display and measurement of snowfield extent, glacier development, sediment plumes from estuary discharge, playa inventory, phreatophyte and other vegetative changes.

Evans, W. E.↗
NASA NTRS1975

Faults on Skylab imagery of the Salton Trough area, Southern California

The author has identified the following significant results. Large segments of the major high angle faults in the Salton Trough area are readily identifiable in Skylab images. Along active faults, distinctive topographic features such as scarps and offset drainage, and vegetation differences due to ground water blockage in alluvium are visible. Other fault-controlled features along inactive as well as active faults visible in Skylab photography include straight mountain fronts, linear valleys, and lithologic differences producing contrasting tone, color or texture. A northwestern extension of a fault in the San Andreas set, is postulated by the regional alignment of possible fault-controlled features. The suspected fault is covered by Holocene deposits, principally windblown sand. A northwest trending tonal change in cultivated fields across Mexicali Valley is visible on Skylab photos. Surface evidence for faulting was not observed; however, the linear may be caused by differences in soil conditions along an extension of a segment of the San Jacinto fault zone. No evidence of faulting could be found along linears which appear as possible extensions of the Substation and Victory Pass faults, demonstrating that the interpretation of linears as faults in small scale photography must be corroborated by field investigations.

Merifield, P. M.↗
NASA NTRS1986

LDV measurements in an annular combustor model

The design and setup of a Laser Doppler Velocimeter (LDV) system used to take velocity measurements in an annular combustor model are covered. The annular combustor model is of contemporary design using 60 degree flat vane swirlers, producing a strong recirculation zone. Detailed measurements are taken of the swirler inlet air flow and of the downstream enclosed swirling flow. The laser system used is a two color, two component system set up in forward scatter. Detailed are some of the special considerations needed for LDV use in the confined turbulent flow of the combustor model. The LDV measurements in a single swirler rig indicated that the flow changes radically in the first duct height. After this, a flow profile is set up and remains constant in shape. The magnitude of the velocities gradually decays due to viscous damping.

Barron, Dean A.↗
NASA NTRS1991

Automated eddy current inspection of Space Shuttle APU turbine wheel blades

An automated inspection system based on eddy current testing (ET) techniques has been developed to inspect turbine wheel blades on the APU used in NASA's Space Transportation system. The APU is a hydrazine-powered gas turbine with a 15-cm diameter Rene 41 turbine wheel, which has 123 first-stage blades and 123 second-stage blades. The flaw detection capability of the ET system is verified through comparison with fluorescent penetrant test results. Results of the comparison indicate that ET is capable of inspecting surfaces with very restrictive geometries. The ET capability requires development of probes with extremely small coils to allow inspection within 0.4 mm of the blade root and the leading and trailing edges of the blade and within a height restriction of less than 1 mm. The color 2D presentation of the ET data provided crack-growth pattern and length information similar to those found with visual techniques. It also provided visual clues to minimize geometry effects such as generated from blade edges, a neighoring blade, and changes in the blade thickness.

Fisher, Jay L.↗
NASA NTRS1993

Global and regional/seasonal color mosaics of Mars

Four regional mosaics of Mars acquired during different seasons, along with their composite as a single global mosaic, have been completed in two colors (red and violet) at scales of 1/16 and 1/64 degrees/pixel. These mosaics were put together from a set of 51 separate mosaics, each acquired from a single Viking orbiter spacecraft orbital revolution. Special techniques were developed and applied to suppress large variations between mosaics introcued by highly variable, optically thin, condensate hazes. The techniques utilize a combination of the spatial characteristics of the hazes (generally broad, low-frequency) along with their modulation of the reginal color ratios (strongly enhancing the violet/red ratios). Photometric-function normalization was applied following the haze removal. Most of the single-orbit mosaics consist of red and violet or red, green, and violet filters, but a few mosaics with only red-filter data were included to fill gaps in global coverage at high northern latitudes. Global coverage is approximately 99 percent complete in red-filter mosaics and approximately 95 percent and approximately 60 percent complete in corresponding violet- and green-filter mosaics, respectively. All of the mosaics are geometrically tied to the 1/256 deg per pixel Mars Digital Image Map (MDIM), which is available on Compact Disk (CD), and which will be used as the base map for Mars Observer data sets. Early in 1993, the single-orbit color mosaics will be distributed to the science community in a six-volume set of CDs. Perhaps the most scientifically interesting parts of this dataset are the overlap regions, which show significant temporal variations in surface and atmospheric features. Surface changes can be categorized as (1) changes that probably occurred during the great dust storms of 1977; (2) changes that occurred soon after 1977 storms due to removal of redistribution of recently deposited dust; (3) changes in the northern lowlands that probably occurred during the dusty southern summer of 1979 (when no great dust storm occurred); and (4) changes associated with strong slope winds in the Tharsis and Elysium regions.

Mcewen, Alfred S.↗
NASA NTRS2012

Applications of MODIS Fluorescent Line Height Measurements to Monitor Water Quality Trends and Algal Bloom Activity

Recent advances in satellite and airborne remote sensing, such as improvements in sensor and algorithm calibrations, processing techniques and atmospheric correction procedures have provided for increased coverage of remote-sensing, ocean-color products for coastal regions. In particular, for the Moderate Resolution Imaging Spectrometer (MODIS) sensor calibration updates, improved aerosol retrievals and new aerosol models has led to improved atmospheric correction algorithms for turbid waters and have improved the retrieval of ocean color in coastal waters. This has opened the way for studying ocean phenomena and processes at finer spatial scales, such as the interactions at the land-sea interface, trends in coastal water quality and algal blooms. Human population growth and changes in coastal management practices have brought about significant changes in the concentrations of organic and inorganic, particulate and dissolved substances entering the coastal ocean. There is increasing concern that these inputs have led to declines in water quality and have increase local concentrations of phytoplankton, which cause harmful algal blooms. In two case studies we present MODIS observations of fluorescence line height (FLH) to 1) assess trends in water quality for Tampa Bay, Florida and 2) illustrate seasonal and annual variability of algal bloom activity in Monterey Bay, California as well as document estuarine/riverine plume induced red tide events. In a comprehensive analysis of long term (2003-2011) in situ monitoring data and satellite imagery from Tampa Bay we assess the validity of the MODIS FLH product against chlorophyll-a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions and to develop a near decadal trend in water quality changes. In situ monitoring locations that correlated well with satellite imagery were in depths greater than seven meters and were located over five kilometers from shore. Water quality parameter of total nitrogen, phosphorous, turbidity and biological oxygen demand had high correlations with these sites, as well. Satellite FLH estimates show improving water quality from 2003-2007 with a slight decline up through 2011. Dinoflagellate blooms in Monterey Bay, California (USA) have recently increased in frequency and intensity. Nine years of MODIS FLH observations are used to describe the annual and seasonal variability of bloom activity within the Bay. Three classes of MODIS algorithms were correlated against in situ chlorophyll measurements. The FLH algorithm provided the most robust estimate of bloom activity. Elevated concentrations of phytoplankton were evident during the months of August-November, a period during which increased occurrences of dinoflagellate blooms have been observed in situ. Seasonal patterns of FLH show the on- and offshore movement of areas of high phytoplankton biomass between oceanographic seasons. Higher concentrations of phytoplankton are also evident in the vicinity of the land-based nutrient sources and outflows, and the cyclonic bay-wide circulation can transport these nutrients to the northern Bay bloom incubation region. Both of these case studies illustrate the utility MODIS FLH observations in supporting management decisions in coastal and estuarine waters.

Fischer, Andrew↗
NASA NTRS2018

Earth Science Engagement Through Art and Astronaut Photography

For over five decades of manned spaceflight missions, NASA astronauts have taken extraordinary photographs of Earth's surface and dynamic processes. Humans on board the International Space Station (ISS) have a unique platform to perform Earth observations at various viewing angles, seasons, and times of day. Astronaut photos taken from the ISS comprise a true‐color (RGB) dataset taken with multiple handheld digital cameras and lens types (prior to 2004, film cameras were in use). Earth observations through astronaut photography are an important and unique remote sensing method when monitoring natural disasters, urban growth, and environmental changes. While astronaut imagery can be used for earth science research, there is also an artistic aspect to the photography that fascinates a wide global population. A broader public audience can be introduced to earth science through high resolution, Earth art photos taken from the perspective of an astronaut. The Crew Earth Observations (CEO) Facility within the Earth Science and Remote Sensing Unit at NASA's Johnson Space Center supports the acquisition, analysis, and curation of astronaut photography of Earth's surface and atmosphere. CEO's website, the Gateway to Astronaut Photography of Earth (eol.jsc.nasa.gov), provides free public access to view, search, and download over three million images taken by astronauts throughout all of NASA's crewed spaceflight history, with an emphasis on current ISS imagery. The CEO Facility actively curates a digital collection of exceptional Earth art astronaut photos used for public engagement. Our new Downloadable Earth Art page focuses on broad earth science topics including: mountains, water, clouds, agriculture, as well as an "abstract" category. This continuously‐updated collection is comprised of freely accessible and high‐quality downloadable materials, such as single‐ and dual‐screen digital wallpapers. All Earth Art materials are presented with science‐based information that complements the artistic qualities of the imagery, and facilitate connections between general audiences and earth science from the International Space Station.

Meado, Andrea L.↗
NASA NTRSDate not supplied

Overview of the MISSE-16 Mission and Preliminary Characterization of Novel Space Weathered Materials

The Materials International Space Station Experiment (MISSE) project is a series of experiments that began in 2001, involving the deployment of external experiment platforms on the International Space Station (ISS). Since then, more than 4,000 materials were tested yielding valuable data and insights into the performance of materials and coatings in the harsh space environment, as well as providing a platform for testing and validating new materials and technologies. The results of the MISSE experiments have contributed to the development of more durable and reliable spacecraft and equipment, as well as improving our understanding of the space environment and its effects on human space exploration. To gain deeper insights into the changes in material properties of both novel and heritage spacecraft materials over the course of a mission, we proposed to enhance the MISSE hardware. This was achieved by integrating a high-resolution camera that can capture both RGB and IR color data, along with an updated illumination scheme. The identical sets of selected materials were mounted on the Zenith, Ram, and Wake faces of the ISS to expose them to predominant vacuum ultraviolet (VUV), atomic oxygen, and high-energy electron conditions. In addition, we exposed flight duplicates of these materials to a simulated space environment, which included sequential exposure to the same irradiation species on the ground. This allowed us to study the effects of space exposure on the materials in a controlled manner and to compare their behavior in both real and simulated space environments. The MISSE-FF flight sample collection comprised different classes of polymers, including polyimides from the Kapton family, manufactured by E.I du Pont de Nemours and Co., Polyethylene terephthalate (PET) materials, liquid crystal polymers, PI/Polyhedral Oligomeric Silsesquioxanes (POSS), and carbon and glass fiber reinforced polymers. The experimental cadence during the MISSE-16 mission (~6 months) included daily images of each sample for the first week, weekly for the next 2 months, and monthly the remaining duration of the mission. This paper will focus on the flight duplicate as well as the postflight optical characterization of novel and heritage materials currently under observation on the MISSE-FF.

Jainisha R Shah↗
NASA NTRS1971

Remote sensing of changes in morphology and physiology of trees under stress

Measurements on foliage samples collected from several drought and salt treated plants revealed that leaf thickness decreased with increasing severity of the drought treatment and increased with increasing severity of treatment with NaCl, but remained essentially unaffected by treatment with CaCl2. Airborne data collected by multispectral scanner indicated that false color images provide selective enhancement of a diseased area. Comparison of simulated and actual aerial color and color IR photography revealed that the color renditions of the MSS simulations agreed closely with those of the actual photography.

Olson, C. E., Jr.↗
NASA NTRS1986

Effect of intervening galaxies on quasar counts and colors

Ostriker and Heisler (1984) suggested that optically thick dust in galaxies could reduce the number of high-redshift quasars without reddening the observed quasars, because the only observed quasars would be those seen through no intervening galaxies. However, Ostriker and Heisler assumed that galaxies were hard-edged uniform disks, and the fuzzy edges of real galaxies significantly change this conclusion. The quasar distribution observed through more realistic galaxy models is calculated, and it is found that dust cannot significantly reduce the high-redshift quasar counts without also reddening the observed sample. But this reddening could be consistent with past studies of quasar reddening; improved studies of quasar reddening using new UV and IR data are needed.

Wright, Edward L.↗
NASA NTRS1987

Basic properties and variability

Giant and supergiant M, S, and C stars are discussed in this survey of research. Basic properties as determined by spectra, chemical composition, photometry, or variability type are discussed. Space motions and space distributions of cool giants are described. Distribution of these stars in our galaxy and those nearby is discussed. Mira variables in particular are surveyed with emphasis on the following topics: (1) phase lag phenomenon; (2) Mira light curves; (3) variations in color indices; (4) determination of multiple periods; (5) correlations between quantities such as period length, light-curve shape, infrared (IR) excess, and visible and IR color diagram; (6) semiregular (SR) variables and different time scales in SR light variations; (7) irregular variable Lb and Lc stars; (8) different time-scale light variations; (9) hydrogen-deficient carbon (HdC) stars, in particular RCB stars; and (10) irreversible changes and rapid evolution in red variable stars.

Querci, Francois R.↗
NASA NTRS1989

A video atlas of TOMS ozone data, 1978-88

The Total Ozone Mapping Spectrometer (TOMS), on-board NASA's Nimbus-7 weather satellite, has been observing ozone over the earth once daily for the last 10 yr. A time-lapse atlas of 3440 color-coded images drawn from the TOMS archive from 1978 to 1988 has been visualized on a standard VHS videotape that is now available from NASA. The rapid and complex ozone variations presented demonstrate the difficulty of separating man-induced climate changes from natural variability. This article presents a few images from the atlas and describes interesting features in the animation, such as the correlation between ozone and 'the weather', and the recent deepening of the annual ozone hole over the South Pole. Originally intended as a browsing tool for the TOMS digital database, the videotape is a vivid presentation of the earth's atmospheric dynamics and chemistry that is recommended for scientists, educators, policy makers, and citizens concerned about the global environment.

Chesters, D.↗
NASA NTRS1992

Cockpit weather information needs

The primary objective is to develop an advanced pilot weather interface for the flight deck and to measure its utilization and effectiveness in pilot reroute decision processes, weather situation awareness, and weather monitoring. Identical graphical weather displays for the dispatcher, air traffic control (ATC), and pilot crew should also enhance the dialogue capabilities for reroute decisions. By utilizing a broadcast data link for surface observations, forecasts, radar summaries, lightning strikes, and weather alerts, onboard weather computing facilities construct graphical displays, historical weather displays, color textual displays, and other tools to assist the pilot crew. Since the weather data is continually being received and stored by the airborne system, the pilot crew has instantaneous access to the latest information. This information is color coded to distinguish degrees of category for surface observations, ceiling and visibilities, and ground radar summaries. Automatic weather monitoring and pilot crew alerting is accomplished by the airborne computing facilities. When a new weather information is received, the displays are instantaneously changed to reflect the new information. Also, when a new surface or special observation for the intended destination is received, the pilot crew is informed so that information can be studied at the pilot's discretion. The pilot crew is also immediately alerted when a severe weather notice, AIRMET or SIGMET, is received. The cockpit weather display shares a multicolor eight inch cathode ray tube and overlaid touch panel with a pilot crew data link interface. Touch sensitive buttons and areas are used for pilot selection of graphical and data link displays. Time critical ATC messages are presented in a small window that overlays other displays so that immediate pilot alerting and action can be taken. Predeparture and reroute clearances are displayed on the graphical weather system so pilot review of weather along the route can be accomplished prior to pilot acceptance of the clearance. An ongoing multiphase test series is planned for testing and modifying the graphical weather system. Preliminary data shows that the nine test subjects considered the graphical presentation to be much better than their current weather information source for situation awareness, flight safety, and reroute decision making.

Scanlon, Charles H.↗
NASA NTRS1998

Physics of Hard Spheres Experiment (PhaSE) or "Making Jello in Space"

The Physics of Hard Spheres Experiment (PHaSE) is a highly successful experiment that flew aboard two shuttle missions to study the transitions involved in the formation of jellolike colloidal crystals in a microgravity environment. A colloidal suspension, or colloid, consists of fine particles, often having complex interactions, suspended in a liquid. Paint, ink, and milk are examples of colloids found in everyday life. In low Earth orbit, the effective force of gravity is thousands of times less than at the Earth's surface. This provides researchers a way to conduct experiments that cannot be adequately performed in an Earth-gravity environment. In microgravity, colloidal particles freely interact without the complications of settling that occur in normal gravity on Earth. If the particle interactions within these colloidal suspensions could be predicted and accurately modeled, they could provide the key to understanding fundamental problems in condensed matter physics and could help make possible the development of wonderful new "designer" materials. Industries that make semiconductors, electro-optics, ceramics, and composites are just a few that may benefit from this knowledge. Atomic interactions determine the physical properties (e.g., weight, color, and hardness) of ordinary matter. PHaSE uses colloidal suspensions of microscopic solid plastic spheres to model the behavior of atomic interactions. When uniformly sized hard spheres suspended in a fluid reach a certain concentration (volume fraction), the particle-fluid mixture changes from a disordered fluid state, in which the spheres are randomly organized, to an ordered "crystalline" state, in which they are structured periodically. The thermal energy of the spheres causes them to form ordered arrays, analogous to crystals. Seven of the eight PHaSE samples ranged in volume fraction from 0.483 to 0.624 to cover the range of interest, while one sample, having a concentration of 0.019, was included for instrument calibration.

Ling, Jerri S.↗
NASA NTRS2012

VIIRS On-Orbit Calibration for Ocean Color Data Processing

The NASA VIIRS Ocean Science Team (VOST) has the task of evaluating Suomi NPP VIIRS ocean color data for the continuity of the NASA ocean color climate data records. The generation of science quality ocean color data products requires an instrument calibration that is stable over time. Since the VIIRS NIR Degradation Anomaly directly impacts the bands used for atmospheric correction of the ocean color data (Bands M6 and M7), the VOST has adapted the VIIRS on-orbit calibration approach to meet the ocean science requirements. The solar diffuser calibration time series and the solar diffuser stability monitor time series have been used to derive changes in the instrument response and diffuser reflectance over time for bands M1-M11.

Eplee, Robert E., Jr.↗