[Electrical and Optical Properties of Glasses in Bismuth Trioxide-Tellurium Dioxide System]
Electrical and optical properties of glasses in bismuth trioxide-tellurium dioxide system
BISMUTH OXIDE↗
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Space Qualification Studies of AOTF Devices Under the MISSE-11 Mission
The acousto-optic tunable filter (AOTF) devices are used in a variety of applications including hyperspectral and spectrapolarimetric based imaging. The AOTF devices provide several advantages including speed and random access to desired spectral bands and enable all-solid-state operation that are attractive for space applications. In this paper, the performance of Tellurium Dioxide (TeO 2 ) and Mercurous Bromide (Hg 2 Br 2 ) AOTF devices in space environment carried out under the NASA’s Materials International Space Station Experiments 11 (MISSE-11) mission is discussed. The purpose of the MISSE-11 mission was to study materials and devices subjected to space conditions for long term while attached to the International Space station (ISS). The TeO 2 AOTF was developed for short wavelength IR (SWIR) operation while the Hg 2 Br 2 AOTF device was developed for long wavelength IR (LWIR) operation. These devices were attached to the ISS platform for more than a year. Pre-flight and post-flight performance characterization were performed on these devices. In the case of TeO 2 AOTF, the preflight efficiency was around 87% with a center frequency at 68MHz while the post-flight efficiency was around 83%. However, the optical transmission of Hg 2 Br 2 AOTF had deteriorated considerably. The details of performance testing and analysis of both AOTF devices are discussed.
Space Qualification↗
Uncertainties in tellurium-based dark matter searches stemming from nuclear structure uncertainties
Using tellurium dioxide as a target, we calculate uncertainties on 90% upper confidence limits of Galilean effective field theory (Galilean EFT) couplings to a weakly interacting massive particle (WIMP) dark matter candidate due to uncertainties in nuclear shell models. We find that these uncertainties in naturally occurring tellurium isotopes are comparable across the different Galilean EFT couplings to uncertainties in xenon, with some reaching over 100%. We also consider the effect these nuclear uncertainties have on estimates of the annual modulation of dark matter from these searches, finding that the uncertainties in the modulation amplitude are proportional to the nonmodulating upper confidence limit uncertainties. We also show that the determination of the modulation phase is insensitive to changes in the nuclear model for a given isotope.
79 ASTRONOMY AND ASTROPHYSICS↗
Shock compression of crystalline TeO 2 to the high-pressure fluid regime: Insights from ab initio molecular dynamics simulations
The shock response of fully-dense and porous crystalline tellurium dioxide (TeO 2 ) to the high-pressure and high-temperature fluid regime was investigated within the framework of density functional theory with Mermin’s generalization to finite temperatures. The principal and porous shock Hugoniot curves were predicted from canonical ab initio molecular dynamics (AIMD) simulations, with the phase space sampled along isotherms up to 80 000 K, for densities ranging from ρ = 3 to 17 g/cm 3 . The polymorphs investigated are α-TeO 2 paratellurite (P4 1 2 1 2), TeO 2 cotunnite (Pnma), and TeO 2 post-cotunnite (P2 1 /m). Based on the discontinuity found in the calculated U s – u p slope of TeO 2 post-cotunnite at a shock velocity of U s ≃ 8.35km/s and a particle velocity of u p ≃ 3.64 km/s, the shock melting temperature and pressure are predicted to be ≃ 6500 K and ≃ 170 GPa. Results from the AIMD simulations are in line with the static compression data of TeO 2 paratellurite and cotunnite, and with the recent shock Hugoniot data for single-crystal α- TeO 2 for pressures up to 85 GPa, obtained using the inclined-mirror method and the velocity interferometer system for any reflector combined with powder gun and two-stage light-gas gun.
74 ATOMIC AND MOLECULAR PHYSICS↗
IR-transmission glasses formed from oxides of bismuth and tellurium
Bismuth trioxide-tellurium dioxide glasses have improved infrared transmission characteristics.
Ulrich, D. R.↗
Polarimetric Multispectral Imaging Technology
The Jet Propulsion Laboratory is developing a remote sensing technology on which a new generation of compact, lightweight, high-resolution, low-power, reliable, versatile, programmable scientific polarimetric multispectral imaging instruments can be built to meet the challenge of future planetary exploration missions. The instrument is based on the fast programmable acousto-optic tunable filter (AOTF) of tellurium dioxide (TeO2) that operates in the wavelength range of 0.4-5 microns. Basically, the AOTF multispectral imaging instrument measures incoming light intensity as a function of spatial coordinates, wavelength, and polarization. Its operation can be in either sequential, random access, or multiwavelength mode as required. This provides observation flexibility, allowing real-time alternation among desired observations, collecting needed data only, minimizing data transmission, and permitting implementation of new experiments. These will result in optimization of the mission performance with minimal resources. Recently we completed a polarimetric multispectral imaging prototype instrument and performed outdoor field experiments for evaluating application potentials of the technology. We also investigated potential improvements on AOTF performance to strengthen technology readiness for applications. This paper will give a status report on the technology and a prospect toward future planetary exploration.
Cheng, L.-J.↗
Acousto-optic infrared spectral imager for Pluto fast flyby
Acousto-optic tunable filters (AOTF's) enable the design of compact, two-dimensional imaging spectrometers with high spectral and spatial resolution and with no moving parts. Tellurium dioxide AOTF's operate from about 400 nm to nearly 5 microns, and a single device will tune continuously over one octave by changing the RF acoustic frequency applied to the device. An infrared (1.2-2.5 micron) Acousto-Optic Imaging Spectrometer (AImS) was designed that closely conforms to the surface composition mapping objectives of the Pluto Fast Flyby. It features a 75-cm focal length telescope, infrared AOTF, and 256 x 256 NICMOS-3 focal plane array for acquiring narrowband images with a spectral resolving power (lambda/delta(lambda)) exceeding 250. We summarize the instrument design features and its expected performance at the Pluto-Charon encounter.
Glenar, D. A.↗
Materials Data on Te4As2S(OF6)2 by Materials Project
(Te)2AsTe2F6AsF6SO2 crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four sulfur dioxide molecules, eight tellurium molecules, four AsF6 clusters, and four AsTe2F6 clusters. In each AsF6 cluster, As1+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.77–1.79 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As1+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As1+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As1+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As1+ atom. In each AsTe2F6 cluster, As1+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.77–1.80 Å. Te4+ is bonded in a 1-coordinate geometry to one F1- atom. The Te–F bond length is 2.97 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As1+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As1+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As1+ and two equivalent Te4+ atoms. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As1+ atom.
36 MATERIALS SCIENCE↗
Materials Data on Te3As2S(OF6)2 by Materials Project
(Te)3AsTeF6AsTe2F6(AsF6)2(SO2)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four sulfur dioxide molecules, six tellurium molecules, four AsF6 clusters, two AsTe2F6 clusters, and two AsTeF6 clusters. In each AsF6 cluster, As5+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.77–1.79 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In each AsTe2F6 cluster, As5+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.75–1.80 Å. There are two inequivalent Te+2.67+ sites. In the first Te+2.67+ site, Te+2.67+ is bonded in a single-bond geometry to one F1- atom. The Te–F bond length is 2.84 Å. In the second Te+2.67+ site, Te+2.67+ is bonded in a single-bond geometry to one F1- atom. The Te–F bond length is 2.82 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Te+2.67+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Te+2.67+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In each AsTeF6 cluster, As5+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.76–1.80 Å. Te+2.67+ is bonded in a distorted single-bond geometry to one F1- atom. The Te–F bond length is 2.86 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Te+2.67+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom.
36 MATERIALS SCIENCE↗