Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Infrared”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

UNVEILING THE NATURE OF UNIDENTIFIED GAMMA-RAY SOURCES. II. RADIO, INFRARED, AND OPTICAL COUNTERPARTS OF THE GAMMA-RAY BLAZAR CANDIDATES

A significant fraction ({approx}30%) of the high-energy gamma-ray sources listed in the second Fermi Large Area Telescope catalog (2FGL) are still of unknown origin, being not yet associated with counterparts at low energies. We recently developed a new association method to identify if there is a {gamma}-ray blazar candidate within the positional uncertainty region of a generic 2FGL source. This method is entirely based on the discovery that blazars have distinct infrared colors with respect to other extragalactic sources found, thanks to the Wide-field Infrared Survey Explorer (WISE) all-sky observations. Several improvements have also been performed to increase the efficiency of our method in recognizing {gamma}-ray blazar candidates. In this paper we applied our method to two different samples, the first constituted by unidentified {gamma}-ray sources (UGSs), and the second by active galaxies of uncertain type, both listed in the 2FGL. We present a catalog of IR counterparts for {approx}20% of the UGSs investigated. Then, we also compare our results for the associated sources with those present in the literature. In addition, we illustrate the extensive archival research carried out to identify the radio, infrared, optical, and X-ray counterparts of the WISE-selected, {gamma}-ray blazar candidates. Finally, we discuss the future developments of our method based on ground-based follow-up observations.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE LOW RESOLUTION SPECTROMETER

Absolute spectrophotometric measurements of diffuse radiation at 1 {mu}m to 2 {mu}m are crucial to our understanding of the radiative content of the universe from nucleosynthesis since the epoch of reionization, the composition and structure of the zodiacal dust cloud in our solar system, and the diffuse galactic light arising from starlight scattered by interstellar dust. The Low Resolution Spectrometer (LRS) on the rocket-borne Cosmic Infrared Background Experiment is a {lambda}/{Delta}{lambda} {approx} 15-30 absolute spectrophotometer designed to make precision measurements of the absolute near-infrared sky brightness between 0.75 {mu}m <{lambda} < 2.1 {mu}m. This paper presents the optical, mechanical, and electronic design of the LRS, as well as the ground testing, characterization, and calibration measurements undertaken before flight to verify its performance. The LRS is shown to work to specifications, achieving the necessary optical and sensitivity performance. We describe our understanding and control of sources of systematic error for absolute photometry of the near-infrared extragalactic background light.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

NEAR-INFRARED H{sub 2} AND CONTINUUM SURVEY OF EXTENDED GREEN OBJECTS. II. COMPLETE CENSUS FOR THE NORTHERN GALACTIC PLANE

We discuss 94 Extended Green Objects (EGOs) in the northern Galactic plane cataloged by Cyganowski et al., based on near-infrared narrow H{sub 2} (2.122 μm) and continuum observations from the United Kingdom Infrared Telescope. This data set is three times larger than the one in our previous study and is unbiased by preselection. As discussed in the previous paper, the morphologies of the 4.5 μm emission generally resemble those of the near-infrared continuum, but are different from those of the H{sub 2} emission. Of our sample, only 28% of EGOs with H{sub 2} emission show similar morphologies between 4.5 μm and H{sub 2} emission. These results suggest that the 4.5 μm emission mainly comes from scattered continuum from the embedded young stellar objects, and partially from H{sub 2} emission. About half of EGOs are associated with H{sub 2} outflows, if the H{sub 2} outflow incompleteness is considered. The H{sub 2} outflow detection rate for EGOs with K-band detections (61%) is significantly higher than for those without K-band detections (36%). This difference may be due to the fact that both H{sub 2} and K-band emissions are associated with outflows, i.e., H{sub 2} emission and K-band continuum are associated with shocks and outflow cavities, respectively. We also compared the correlation between the H{sub 2} outflows and Class I 44 GHz methanol masers from the literature. The methanol masers can be located upstream or downstream of the H{sub 2} outflows and some bright H{sub 2} spots or outflows are not associated with methanol masers, suggesting that methanol masers and H{sub 2} emission trace different excitation conditions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

S-CANDELS: The Spitzer-cosmic assembly near-infrared deep extragalactic survey. Survey design, photometry, and deep IRAC source counts

The Spitzer-Cosmic Assembly Deep Near-infrared Extragalactic Legacy Survey (S-CANDELS; PI G.Fazio) is a Cycle 8 Exploration Program designed to detect galaxies at very high redshifts (z>5). To mitigate the effects of cosmic variance and also to take advantage of deep coextensive coverage in multiple bands by the Hubble Space Telescope (HST) Multi-cycle Treasury Program CANDELS, S-CANDELS was carried out within five widely separated extragalactic fields: the UKIDSS Ultra-deep Survey, the Extended Chandra Deep Field South, COSMOS, the HST Deep Field North, and the Extended Groth Strip. S-CANDELS builds upon the existing coverage of these fields from the Spitzer Extended Deep Survey (SEDS), a Cycle 6 Exploration Program, by increasing the integration time from SEDS’ 12 hr to a total of 50 hr but within a smaller area, 0.16 deg{sup 2}. The additional depth significantly increases the survey completeness at faint magnitudes. This paper describes the S-CANDELS survey design, processing, and publicly available data products. We present Infrared Array Camera (IRAC) dual-band 3.6+4.5 μm catalogs reaching to a depth of 26.5 AB mag. Deep IRAC counts for the roughly 135,000 galaxies detected by S-CANDELS are consistent with models based on known galaxy populations. The increase in depth beyond earlier Spitzer/IRAC surveys does not reveal a significant additional contribution from discrete sources to the diffuse Cosmic Infrared Background (CIB). Thus it remains true that only roughly half of the estimated CIB flux from COBE/DIRBE is resolved.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Plasmonic nanopatch array with integrated metal–organic framework for enhanced infrared absorption gas sensing

In this letter, we present a nanophotonic device consisting of plasmonic nanopatch array (NPA) with integrated metal–organic framework (MOF) for enhanced infrared absorption gas sensing. By designing a gold NPA on a sapphire substrate, we are able to achieve enhanced optical field that spatially overlaps with the MOF layer, which can adsorb carbon dioxide (CO 2 ) with high capacity. Additionally, experimental results show that this hybrid plasmonic–MOF device can effectively increase the infrared absorption path of on-chip gas sensors by more than 1100-fold. Lastly, the demonstration of infrared absorption spectroscopy of CO 2 using the hybrid plasmonic–MOF device proves a promising strategy for future on-chip gas sensing with ultra-compact size.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Ultrafast infrared plasmon switching in aligned carbon-nanotube optical resonators

Reconfigurable plasmonic materials are crucial components in active photonic devices for optical communication, signal processing, and sensing applications. Certain candidates including transparent conducting oxides, small-bandgap semiconductors (i.e. Ge, InSb), and conducting polymers can exhibit switchable free carrier concentrations triggered by optical, electrical or thermal excitations. Here, we show that aligned films of single-walled carbon nanotubes (SWCNTs) can serve as all-optically tunable plasmonic material in the mid-infrared range, thereby adding them to the library of switchable plasmonic materials. Interband optical pumping with femtosecond laser pulses results in the photoexcitation of free charge carriers, which transiently blueshifts the plasmon resonances of patterned, periodic SWCNT nano-resonators spanning the mid-infrared spectral range from 1700 to 2700 cm -1 . Furthermore. the ultrafast plasmon modulation exhibits a nearly single-picosecond decay time, attributed to interband carrier relaxation and inter-tube charge transfer. Given that aligned films of SWCNTs have high thermal stability, excellent photostability, epsilon-near-zero property, and extremely large optical anisotropy, their dynamic tunability represents a promising pathway towards active optical devices in the technologically important mid-infrared range.

single-walled carbon nanotubes↗
DOE OSTI2013

THE MID-INFRARED LIGHT CURVE OF NEARBY CORE-COLLAPSE SUPERNOVA SN 2011dh (PTF 11eon)

We present Spitzer observations at 3.6 and 4.5 μm of the supernova SN 2011dh (PTF 11eon) in M51 from 18 days to 625 days after explosion. The mid-infrared emission peaks at 24 days after explosion at a few ×10{sup 7} L {sub ☉}, and decays more slowly than the visible-light bolometric luminosity. The infrared color temperature cools for the first 90 days and then is constant. Simple numerical models of a thermal echo can qualitatively reproduce the early behavior. At late times, the mid-IR light curve cannot be explained by a simple thermal echo model, suggesting additional dust heating or line emission mechanisms. We also propose that thermal echoes can serve as effective probes to uncover supernovae in heavily obscured environments, and speculate that under the right conditions, integrating the early epoch of the mid-infrared light curve may constrain the total energy in the shock breakout flash.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

MID-INFRARED HIGH-CONTRAST IMAGING OF HD 114174 B: AN APPARENT AGE DISCREPANCY IN A ''SIRIUS-LIKE'' BINARY SYSTEM

We present new observations of the faint ''Sirius-like'' companion discovered to orbit HD 114174. Previous attempts to image HD 114174 B at mid-infrared wavelengths using NIRC2 at Keck have resulted in a non-detection. Our new L'-band observations taken with the Large Binocular Telescope and L/M-band InfraRed Camera recover the companion (ΔL = 10.15 ± 0.15 mag, ρ = 0.''675 ± 0.''016) with a high signal-to-noise ratio (10σ). This measurement represents the deepest L' high-contrast imaging detection at subarcsecond separations to date, including extrasolar planets. We confirm that HD 114174 B has near-infrared colors consistent with the interpretation of a cool white dwarf (WD; J – L' = 0.76 ± 0.19 mag, K – L' = 0.64 ± 0.20). New model fits to the object's spectral energy distribution indicate a temperature T {sub eff} = 4260 ± 360 K, surface gravity log g = 7.94 ± 0.03, a cooling age t{sub c} ≈ 7.8 Gyr, and mass M = 0.54 ± 0.01 M {sub ☉}. We find that the cooling ages given by theoretical atmospheric models do not agree with the age of HD 114174 A derived from both isochronological and gyrochronological analyses. We speculate on possible scenarios to explain the apparent age discrepancy between the primary and secondary. HD 114174 B is a nearby benchmark WD that will ultimately enable a dynamical mass estimate through continued Doppler and astrometric monitoring. Efforts to characterize its physical properties in detail will test theoretical atmospheric models and improve our understanding of WD evolution, cooling, and progenitor masses.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

A LUMINOUS BLUE VARIABLE STAR INTERACTING WITH A NEARBY INFRARED DARK CLOUD

G79.29+0.46 is a nebula created by a luminous blue variable (LBV) star candidate characterized by two almost circular concentric shells. In order to investigate whether the shells are interacting with the infrared dark cloud (IRDC) G79.3+0.3 located at the southwestern border of the inner shell, we conducted Jansky Very Large Array observations of NH{sub 3}(1, 1), (2, 2) and c-C{sub 3}H{sub 2}, and combined them with previous Effelsberg data. The overall NH{sub 3} emission consists of one main clump, named G79A, elongated following the shape of the IRDC, plus two fainter and smaller cores to the north, which spatially match the inner infrared shell. We analyzed the NH{sub 3} spectra at each position with detected emission and inferred linewidth, rotational temperature, column density, and abundance maps, and find that: (1) the linewidth of NH{sub 3}(1, 1) in the northern cores is 0.5 km s{sup –1}, slightly larger than in their surroundings; (2) the NH{sub 3} abundance is enhanced by almost one order of magnitude toward the northwestern side of G79A; (3) there is one ''hot slab'' at the interface between the inner infrared shell and the NH{sub 3} peak of G79A; and (4) the western and southern edges of G79A present chemical differentiation, with c-C{sub 3}H{sub 2} tracing more external layers than NH{sub 3}, similar to what is found in photon-dominated regions. Overall, the kinematics and physical conditions of G79A are consistent with both shock-induced and UV radiation-induced chemistry driven by the LBV star. Therefore, the IRDC is not likely associated with the star-forming region DR15, but located farther away, near G79.29+0.46 at 1.4 kpc.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

THE DROP DURING LESS THAN 300 DAYS OF A DUSTY WHITE DWARF'S INFRARED LUMINOSITY

We report Spitzer/Infrared Array Camera photometry of WD J0959–0200, a white dwarf that displays excess infrared radiation from a disk, likely produced by a tidally disrupted planetesimal. We find that in 2010, the fluxes in both 3.6 μm and 4.5 μm decreased by ∼35% in less than 300 days. The drop in the infrared luminosity is likely due to an increase of the inner disk radius from one of two scenarios: (1) a recent planetesimal impact; (2) instability in the circumstellar disk. The current situation is tantalizing; high-sensitivity, high-cadence infrared studies will be a new tool to study the interplay between a disk and its host white dwarf star.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

THE VARIABLE NEAR-INFRARED COUNTERPART OF THE MICROQUASAR GRS 1758–258

We present a new study of the microquasar system GRS 1758–258 in the near-infrared domain based on archival observations with the Hubble Space Telescope and the NICMOS camera. In addition to confirming the near-infrared counterpart pointed out by Muñoz-Arjonilla et al., we show that this object displays significant photometric variability. From its average magnitudes, we also find that GRS 1758–258 fits well within the correlation between the optical/near-infrared and X-ray luminosity known to exist for low-mass, black-hole candidate X-ray binaries in a hard state. Moreover, the spectral energy distribution built using all radio, near-infrared, and X-ray data available closest in time to the NICMOS observations can be reasonably interpreted in terms of a self-absorbed radio jet and an irradiated accretion disk model around a stellar-mass black hole. All these facts match the expected behavior of a compact binary system and strengthen our confidence in the counterpart identification.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

A YOUNG WHITE DWARF WITH AN INFRARED EXCESS

Using observations of Spitzer/IRAC, we report the serendipitous discovery of excess infrared emission from a single white dwarf PG 0010+280. At a temperature of 27,220 K and a cooling age of 16 Myr, it is the hottest and youngest white dwarf to display an excess at 3–8 μm. The infrared excess can be fit by either an opaque dust disk within the tidal radius of the white dwarf or a 1300 K blackbody, possibly from an irradiated substellar object or a re-heated giant planet. PG 0010+280 has two unique properties that are different from white dwarfs with a dust disk: (i) relatively low emission at 8 μm and (ii) non-detection of heavy elements in its atmosphere from high-resolution spectroscopic observations with Keck/HIRES. The origin of the infrared excess remains unclear.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Direct Observation of Infrared Plasmonic Fano Antiresonances by a Nanoscale Electron Probe

In this report, we exploit recent breakthroughs in monochromated aberration-corrected scanning transmission electron microscopy (STEM) to resolve infrared plasmonic Fano antiresonances in individual nanofabricated disk-rod dimers. Using a combination of electron energy-loss spectroscopy and theoretical modeling, we investigate and characterize a subspace of the weak coupling regime between quasi-discrete and quasi-continuum localized surface plasmon resonances where infrared plasmonic Fano antiresonances appear. Our research illustrates the capability of STEM instrumentation to experimentally observe nanoscale plasmonic responses that were previously the domain only of higher-resolution infrared spectroscopies.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Infrared nanospectroscopy characterization of metal oxide photoresists

Implementation of extreme ultraviolet (EUV) lithography in high-volume semiconductor manufacturing requires a reliable and scalable EUV resist platform. A mechanistic understanding of the pros and cons of different EUV resist materials is critically important. However, most material characterization methods with nanometer resolution use an x-ray photon or electron beam as the probe, which often cause damage to the photoresist film during measurement. Here, we illustrated the use of non-destructive infrared nanospectroscopy [or nano-Fourier-Transform infrared spectroscopy (nano-FTIR)] to obtain spatially resolved composition information in patterned photoresist films. Further, clear evidence of exposure-induced chemical modification was observed at a spatial resolution down to 40 nm, well below the diffraction limit of infrared light. With improvements, such a nano-FTIR technique with nanoscale spatial resolution, chemical sensitivity, and minimal radiation damage can be a promising candidate for the fundamental study of material properties relevant to EUV lithography.

36 MATERIALS SCIENCE↗
DOE OSTI2014

The Northwest Infrared (NWIR) gas-phase spectral database of industrial and environmental chemicals: Recent updates

With continuing improvements in both standoff- and point-sensing techniques, there is an ongoing need for high-quality infrared spectral databases. The Northwest Infrared Database (NWIR) contains quantitative, gas-phase infrared spectra of nearly 500 pure chemical species that can be used for a variety of applications such as atmospheric monitoring, biomass burning studies, etc. The data, recorded at 0.1 cm-1 resolution, are pressure broadened to one atmosphere (N2) in order to mimic atmospheric conditions. Each spectrum is a composite composed of multiple individual measurements. Recent updates to the database include over 60 molecules that are known or suspected biomass-burning effluents. Examples from this set of measurements will be presented and experimental details will be discussed in the context of the utility of NWIR for environmental applications.

quantitative infrared spectra, absorption cross-se↗
DOE OSTI2015

Broadband infrared vibrational nano-spectroscopy using thermal blackbody radiation

Infrared vibrational nano-spectroscopy based on scattering scanning near-field optical microscopy (s-SNOM) provides intrinsic chemical specificity with nanometer spatial resolution. Here we use incoherent infrared radiation from a 1400 K thermal blackbody emitter for broadband infrared (IR) nano-spectroscopy.With optimized interferometric heterodyne signal amplification we achieve few-monolayer sensitivity in phonon polariton spectroscopy and attomolar molecular vibrational spectroscopy. Near-field localization and nanoscale spatial resolution is demonstrated in imaging flakes of hexagonal boron nitride (hBN) and determination of its phonon polariton dispersion relation. The signal-to-noise ratio calculations and analysis for different samples and illumination sources provide a reference for irradiance requirements and the attainable near-field signal levels in s-SNOM in general. As a result, the use of a thermal emitter as an IR source thus opens s-SNOM for routine chemical FTIR nano-spectroscopy.

36 MATERIALS SCIENCE↗
DOE OSTI2019

PBX-9501 High Explosive Infrared Thermography Test Report

High explosive safety requirements put in place by the Department of Defense necessitate that Los Alamos National Laboratory verify that high melting explosive-based plastic bonded explosive 9501 will not present a health or safety risk to personnel when exposed to various accident scenarios. The JT5R-14C test is being developed to validate this requirement in a scenario where PBX-9501 is exposed to a hydrocarbon fuel fire. Preliminary testing is required to establish benchmark data on the burning characteristics of PBX-9501. The PBX-9501 High Explosive Infrared Thermography test was designed to provide the benchmark burning characteristics of PBX-9501 in a simulated fuel fire environment using propane burners as a fuel source. The PBX-9501-HEIT was successfully completed using a 20.32 cm tall cylindrical sample of PBX-9501 with a radius of 10.16 cm, a volume of 6,589.63 cm 3 , a density of 1.83 g/cm 3 , and a mass of 1.2 kg. The PBX-9501-HEIT test was captured and recorded video sequence using a Telops Inc., Multispectral Infrared camera. The infrared sequence was reviewed to identify key events throughout the test and serves as a visual tool to cross reference against future testing to aid in the identification of PBX-9501 high explosive ignition and deflagration characteristics. The data obtained in the thermographic sequence confirmed that the temperatures emitted by the PBX-9501 were higher than the temperatures of the propane burner ignition source. The propane burner flames had a temperature range of 700-850 °C. The cylindrical sample of PBX-9501 burned at an average temperature of 1000-1200 °C on the surface with off-gassing temperatures averaging 1100-1250 °C. The heat map of the PBX-9501 obtained through the test was between 250-550 °C higher than the propane gas temperatures. The temperature differential between the PBX-9501 and the propane flame allowed for the identification of key burning features.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2021

p-i-n High-Speed Photodiodes for X-RAY and Infrared Imagers Fabricated by In-Situ -Doped APCVD Germanium Homoepitaxy

Design, simulation, fabrication, and measurement have been performed using a new method for obtaining high-speed p-i-n germanium photodiodes for use in backside imaging arrays. These devices are proof-of-principal in situ-doped vertical mesa structures fabricated using single-wafer, atmospheric-pressure chemical vapor deposition (APCVD) homoepitaxy on Czochralski-grown Ge substrates. Excellent impurity profiles resulting from in situ doping, as measured by spreading-resistance profilometry, were 5 × 10 16 , 2 × 10 15 , and 2 × 10 18 (cm -3 ) for the p-type anode, i-region absorber, and n+ cathode, respectively. Scanning electron microscopy analysis revealed very-low defect densities in the epitaxial layers. The diodes, with diameters ranging 100-500 μm, exhibited excellent ideality (n = 1.15) and less than 1-μA dark current, corresponding to up to 80 kV-cm -1 electric field in the smallest devices. Avalanche breakdown bias was consistently at a magnitude of 50 V or lower. External quantum efficiencies in the near-infrared spectrum peaked at 70%. Pulsed illumination experiments, both in the infrared and X-ray regions, showed pulse rise times in the 100-140 ps range, indicating excellent applicability of this method to high-speed X-ray or infrared applications.

36 MATERIALS SCIENCE↗