| Imaging Disk Distortion of Be Binary System Delta Scorpii Near Periastron |
20 Sep 2012 |
19 pages |
| Authors:
X Che; J D Monnier; C Tycner; S Kraus; R T Zavala; F Baron; E Pedretti; T ten Brummelaar; H McAlister; S T Ridgway; NAVAL OBSERVATORY FLAGSTAFF AZ
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 | The highly eccentric Be binary system δ Sco reached periastron during early 2011 July, when the distance between the primary and secondary was a few times the size of the primary disk in the H band. This opened a window of opportunity to study how the gaseous disks around Be stars respond to gravitational disturbance. We first refine the binary parameters with the best orbital phase coverage data from the ... |
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| Optical Observations With Milliarcsecond Resolution Of Stars, Their Environments And Companions |
Jan 2012 |
6 pages |
| Authors:
Jason J Sanborn; Robert T Zavala; NAVAL OBSERVATORY FLAGSTAFF AZ
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| Observations with milliarcsecond resolution using the Navy Optical Interferometer have been obtained for a number of stellar systems which include high-mass binaries, eclipsing binaries, and radio stars. These observations also reveal the previously unseen companions in single-lined spectroscopic binaries via directly measured flux ratios. We will present examples of published and ongoing research efforts of these systems to illustrate how an optical interferometer contributes to our knowledge of stars, their ... |
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| Visual Orbit Solutions from Observing Techniques Old and New |
Jan 2012 |
9 pages |
| Authors:
Brian D Mason; NAVAL OBSERVATORY WASHINGTON DC
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| For the past couple of decades, the primary double star observational technique utilized at the US Naval Observatory has been speckle interferometry. Our two speckle cameras have been used on a variety of telescopes: our 26 in Washington, the USNO (NOFS) 61, the McDonald 82, the Mt. Wilson 100 and the twin 4 meter telescopes of KPNO and CTIO. While these instruments have each yielded many observations, they have been ... |
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| Development of a Space Flight Prototype Doppler Asymmetric Spatial Heterodyne (DASH) Spectrometer for the Measurement of Upper Atmospheric Winds |
31 Oct 2011 |
60 pages |
| Authors:
David D Babcock; ARTEP INC ELLICOTT CITY MD
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| This report provides a summary of the progress in developing and testing a space flight prototype Doppler Asymmetric Spatial Heterodyne (DASH) interferometer, for the purposes of measuring winds in the Mesosphere and Lower Thermosphere/Ionosphere (MLTI). The motivation behind developing a prototype instrument during this SBIR Phase II is to raise the technical readiness level (TRL). |
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| Interferometric Imaging of Geostationary Satellites: Signal-to-Noise Considerations |
Sep 2011 |
10 pages |
| Authors:
Anders M Jorgensen; H R Schmidt; D Mozurkewich; J T Armstrong; S Restaino; R L Hindsley; NAVAL RESEARCH LAB WASHINGTON DC
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| Geostationary satellites are generally too small to image at high resolution with conventional single-dish tele- scopes. Obtaining many resolution elements across a typical geostationary satellite body requires a single-dish telescope with a diameter of 10's of m or more, with a good adaptive optics system. An alternative is to use an optical/infrared interferometer consisting of multiple smaller telescopes in an array configuration. In this paper and companion papers1, 2 we ... |
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| Simulated Synthesis Imaging of Geostationary Satellites |
Sep 2011 |
7 pages |
| Authors:
Henrique R Schmitt; David Mozurkewich; Anders M Jorgensen; Sergio R Restaino; J T Armstrong; Ellyn K Baines; Robert B Hindsley; COMPUTATIONAL PHYSICS INC SPRINGFIELD VA
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| We simulate observations of a satellite using various optical interferometer configurations, and reconstruct images with aperture synthesis techniques from these simulated observations. We compare the typical Y-shaped interferometer design to arrays of 30 telescopes on either a redundant or a non-redundant hexagonal grid and to an array mounted on a linear movable boom, all with multiple spectral channels covering a broad wavelength range. We investigate the number of telescopes, the ... |
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| Holographic Interferometry of Oil Films and Droplets in Water with a Single-Beam Mirror-Type Scheme |
01 MAR 2011 |
6 pages |
| Authors:
Nickolai Kukhtarev; Tatiana Kukhtareva; Sonia C. Gallegos; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Application of single-beam reflective laser optical interferometry for oil films and droplets in water detection and characterization is discussed Oil films can be detected by the appearance of characteristic interference patterns. Analytical expressions describing intensity distribution in these interference patterns allow determination of oil film thickness, size of oil droplets, and distance to the oil film from the observation plane Results from these analyses indicate that oil spill aging and ... |
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| Analyzing the delta Sco Binary in Anticipation of a Disk-Star Collision |
Jan 2011 |
3 pages |
| Authors:
Ashley Ames; Christopher Tycner; Robert Zavala; NAVAL OBSERVATORY FLAGSTAFF AZ
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| A current investigation is underway into the possible collision between a circumstellar disk and the secondary star in the delta Scorpii binary system. Delta Scorpii is a prime candidate for a disk-star collision since the primary star has a circumstellar disk and the secondary star has a highly elliptical orbit with a period of approximately 10.5 years making the periastron passage very close to the primary star. The Navy Prototype ... |
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| Detection of a Geostationary Satellite with the Navy Prototype Optical Interferometer |
JUL 2010 |
9 pages |
| Authors:
J. T. Armstrong; R. B. Hindsley; H. R. Schmitt; F. J. Vrba; J. A. Benson; D. J. Hutter; R. T. Zavala; NAVAL RESEARCH LAB WASHINGTON DC
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| We have detected a satellite via optical interferometry for the first time, using a 16 m baseline of the Navy Prototype Optical Interferometer (NPOI) to observe the geostationary communications satellite DirecTV-9S during the "glint" seasons of February-March 2008 and 2009 when the sun-satellite-NPOI geometry was favorable for causing specular reflections from geostationary satellites. We used the US Naval Observatory Flagstaff Station 1 m telescope to generate accurate positions for steering ... |
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| The Spatially Resolved H(alpha)-Emitting Wind Structure of P Cygni |
Jun 2010 |
11 pages |
| Authors:
Aurelian Balan; C Tycner; R T Zavala; J A Benson; D J Hutter; M Templeton; NAVAL OBSERVATORY FLAGSTAFF AZ
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| High spatial resolution observations of the H(alpha)-emitting wind structure associated with the luminous blue variable star P Cygni were obtained with the Navy Prototype Optical Interferometer. These observations represent the most comprehensive interferometric data set on P Cyg to date. We demonstrate how the apparent size of the H(alpha)-emitting region of the wind structure of P Cyg compares between the 2005, 2007, and 2008 observing seasons and how this relates ... |
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| From Fringes to the USNO Navy Prototype Optical Interferometer Astrometric Catalog |
2010 |
10 pages |
| Authors:
J. A. Benson; D. J. Hutter; R. T. Zavala; H. C. Harris; P. D. Shankland; K. J. Johnston; NAVAL OBSERVATORY FLAGSTAFF AZ
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| We report progress on the United States Naval Observatory, Navy Prototype Optical Interferometer, Astrometric Catalog (UNAC). This catalog uses observations from eight astrometric observation runs (Jan. 2005 - Nov. 2009) at the Navy Prototype Optical Interferometer (NPOI). The goal of the first release of the UNAC is to provide an astrometric catalog of at least 100 bright (V < 6) stars with precise positions accurate to < 16 milliarcseconds. In ... |
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| Micromachined Resonators of High Q-factor Based on Atomic Layer Deposited Alumina |
Jan 2009 |
10 pages |
| Authors:
Yuan-Jeng Chang; Jason M Gray; Atif Imtiaz; Dragos Seghete; T M Wallis; Steven M George; Pavel Kabos; CHARLES T ROGERS; Victor M Bright; COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING
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| In this paper, atomic layer deposited (ALD) alumina (Al2O3) has been demonstrated as the structural material for a micro-resonator for the first time. An electrostatically actuated micro-bridge made of chromium (Cr) coated ALD Al2O3 was used as a resonator. The resonatorwas formed by simplewet- and dry-etching processes. The static displacement profile of the micro-resonator under electrostatic load was measured by an optical interferometer. A model of a pinned?pinned beam with ... |
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| Oscillations in a Forward-Facing Cavity Measured Using Laser-Differential Interferometry in a Hypersonic Quiet Tunnel |
11 DEC 2007 |
151 pages |
| Authors:
Rodrigo Segura; PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS
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| Laminar-turbulent transition is a pivotal factor for the design of hypersonic vehicles but the mechanisms that induce transition are not well understood. A laser differential interferometer (LDI) is a non-intrusive optical device that measures the optical path length difference between two laser beams. The LDI is a reliable calibrated instrument to assist the study of boundary layer instability-wave growth in hypersonic flow and has high sensitivity and frequency response. An ... |
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| Doppler Asymmetric Spatial Heterodyne Spectroscopy (DASH): Concept and Experimental Demonstration |
10 OCT 2007 |
12 pages |
| Authors:
Christoph R. Englert; David D. Babcock; John M. Harlander; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
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| We describe the concept of Doppler asymmetric spatial heterodyne spectroscopy (DASH) and present a laboratory Doppler-shift measurement using an infrared laser line. DASH is a modification of spatial heterodyne spectroscopy optimized for high precision, high accuracy Doppler-shift measurements of atmospheric emission lines either from the ground or a satellite. We discuss DASH design considerations, field widening, thermal stability and tracking, noise propagation, advantages, and trade-offs. DASH interferometers do not require ... |
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| O Type and Other Hot Binaries: Current Statistics of the USNO Database |
01-Jan-2007 |
11 pages |
| Authors:
Brian D Mason; NAVAL OBSERVATORY WASHINGTON DC
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| The first speckle survey of O stars (Mason et al. 1998) conducted on NOAO 4-m telescopes in 1994-6 had success far in excess of our expectations. In addition to the conclusions in the multiplicity analysis, many of the new systems which were first resolved in this paper have very significant astrophysical interest. This updates the statistics from 1998 based on new results from the double star catalogs maintained at the ... |
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| Optical Interferometric Observations of Theta1 Orionis C from NPOI and Implications for the System Orbit (Preprint) |
2007 |
14 pages |
| Authors:
J. Patience; R. T. Zavala; L. Prato; O. Franz; L. Wasserman; C. Tycner; D. J. Hutter; C. A. Hummel; EXETER UNIV (UNITED KINGDOM) SCHOOL OF PHYSICS
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| With the Navy Prototype Optical Interferometer (NPOI), the binary system Theta 1 Orionis C, the most massive member of the Trapezium, was spatially resolved over a time period extending from February 2006 to March 2007. The data show significant orbital motion over the 14 months, and, after combining the NPOI data with previous measurements of the system from the literature, the observations span 10 years of the orbit. Our results ... |
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| The Status and Future of the ICRF |
DEC 2006 |
7 pages |
| Authors:
A. L. Fey; NAVAL OBSERVATORY WASHINGTON DC
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| The International Celestial Reference Frame (ICRF) is currently defined by the radio positions of 212 extragalactic objects. Since its inception there have been two extensions to the ICRF. These extensions included revised positions of ICRF candidate and "other" sources, based on inclusion of additional observations, as well as positions of an additional 109 "new" sources. With continued applicable Very Long Baseline Interferometry (VLBI) observations and improvements in analysis a better ... |
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| Basic Studies on High Pressure Air Plasmas |
30 AUG 2006 |
35 pages |
| Authors:
Karl H. Schoenbach; OLD DOMINION UNIV RESEARCH FOUNDATION NORFOLK VA
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| This project focuses on the development of diagnostic methods for electron density and gas temperature measurements of microdischarges in atmospheric pressure air, two of the most important plasma parameters for any plasma application. Two types of diagnostic techniques have being explored: emission spectroscopy for temperature measurements and two wavelength laser heterodyne interferometry for electron density. They were applied to glow discharges in atmospheric pressure air with dimensions in the millimeter ... |
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| Coherent Integrations, Fringe Modeling, and Bootstrapping With the NPOI |
MAY 2006 |
13 pages |
| Authors:
Anders M. Jorgensen; Dave Mozurkewich; Henrique Schmitt; J. T. Armstrong; G. C. Gilbreath; Robert Hindsley; Thomas A. Pauls; Deane M. Peterson; LOS ALAMOS NATIONAL LAB NM
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| Atmospheric turbulence is a major impediment to ground-based optical interferometry. It causes fringes to move on ms time-scales, forcing very short exposures. Because of the semi-random phase shifts, the traditional approach averages exposure power spectra to build signal-to-noise ratio (SNR). This incoherent average has two problems: (1) A bias of correlated noise is introduced which must be subtracted. The smaller the visibility/the fainter the target star, the more difficult bias ... |
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| The Hyades Binary Theta2 Tauri: Confronting Evolutionary Models With Optical Interferometry |
MAY 2006 |
10 pages |
| Authors:
J. T. Armstrong; D. Mozurkewich; Arsen R. Hajian; K. J. Johnston; R. N. Thessin; Deane M. Peterson; C. A. Hummel; G. C. Gilbreath; NAVAL RESEARCH LAB WASHINGTON DC REMOTE SENSING DIV
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| We determine the masses and magnitude difference of the components of the Hyades spectroscopic binary theta(2) Tauri. We find that both components appear to be less massive and/or brighter than predicted from some recent evolutionary models. The rapid rotation and unknown rotational inclination of both components introduce uncertainty in their luminosities and colors, but not enough to reconcile both of them with the evolutionary models. We measured the visual orbit ... |
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| Constraining Disk Parameters of Be Stars Using Narrowband Halpha Interferometry With the Navy Prototype Optical Interferometer |
MAY 2006 |
13 pages |
| Authors:
Christopher Tycner; G. C. Gilbreath; R. T. Zavala; J. T. Armstrong; J. A. Benson; Arsen R. Hajian; D. J. Hutter; C. E. Jones; T. A. Pauls; N. M. White; NAVAL OBSERVATORY FLAGSTAFF AZ
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| Interferometric observations of two well-known Be stars, gamma Cas and phi Per, were collected and analyzed to determine the spatial characteristics of their circumstellar regions. The observations were obtained using the Navy Prototype Optical Interferometer equipped with custom-made narrowband filters. The filters isolate the H(alpha) emission line from the nearby continuum radiation, which results in an increased contrast between the interferometric signature due to the H(alpha)-emitting circumstellar region and the ... |
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| Vega is a Rapidly Rotating Star |
13 APR 2006 |
5 pages |
| Authors:
D. M. Peterson; C. A. Hummel; T. A. Pauls; J. T. Armstrong; J. A. Benson; G. C. Gilbreath; R. B. Hindsley; D. J. Hutter; K. J. Johnston; D. Mozurkewich; STATE UNIV OF NEW YORK AT STONY BROOK DEPT OF PHYSICS AND ASTRONOMY
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| Vega, the second brightest star in the northern hemisphere, serves as a primary spectral type standard. Although its spectrum is dominated by broad hydrogen lines, the narrower lines of the heavy elements suggested slow to moderate rotation, giving confidence that the ground-based calibration of its visible spectrum could be safely extrapolated into the ultraviolet near-infrared (through atmosphere models), where it also serves as the primary photometric calibrator. But there have ... |
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| Resolving the Effects of Rotation in Altair with Long-Baseline Interferometry |
10 JAN 2006 |
12 pages |
| Authors:
D. M. Peterson; C. A. Hummel; T. A. Pauls; J. T. Armstrong; J. A. Benson; G. C. Gilbreath; D. J. Hutter; K. J. Johnston; D. Mozurkewich; H. Schmitt; STATE UNIV OF NEW YORK AT STONY BROOK DEPT OF PHYSICS AND ASTRONOMY
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| We report the successful fitting of a Roche model, with a surface temperature gradient following the von Zeipel gravity darkening law, to observations of Altair made with the Navy Prototype Optical Interferometer. We confirm the claim by Ohishi et al. that Altair displays an asymmetric intensity distribution due to rotation, the first such detection in an isolated star. Instrumental effects due to the high visible flux of this first magnitude ... |
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| Early Type Stars as Calibrators for Ground-Based Interferometry |
2006 |
8 pages |
| Authors:
Jinmi Yoon; Deane M. Peterson; Thomas Amstrong; James H. Clark III; Charmaine Gilbreath; Thomas Pauls; Henrique R. Schmitt; STATE UNIV OF NEW YORK AT STONY BROOK DEPT OF PHYSICS AND ASTRONOMY
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| Visibility measurements with Michelson interferometers, particularly the measurement of fringe contrast, are affected by various atmospheric and instrumental effects, all of which reduce the measured contrast. To compensate for this, stars with known or predictable diameters (calibrators) are observed so that the overall reduction in the visibility can be measured. Objects with the smallest possible diameters are preferred as calibrators, since the predicted visibilities become less sensitive to any uncertainties. ... |
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| Passive Optical Detection of Underwater Sound |
31 MAY 2005 |
24 pages |
| Authors:
Lynn T. Antonelli; DEPARTMENT OF THE NAVY WASHINGTON DC
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| The invention, as embodied herein, comprises a passive acoustic sensor used for detecting sounds emanating from under the surface of a body of water. Specifically, the invention is designed to operate in an ocean environment, wherein turbulent waters are prevalent. Rather than employ standard hydrophones placed beneath the water to detect sound, the present invention detects sound pressure waves that occur when sound is emanated from within a body of ... |
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| Optical Underwater Acoustic Sensor |
25 FEB 2005 |
16 pages |
| Authors:
Lynn T. Antonelli; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An acoustic sensor used in underwater applications. The sensor includes a reflective material adhered to one side of a structure, such as an outer submarine hull or any marine vessel hull. A laser interferometer is placed on the side of the structure with the reflective material. The laser interferometer sends a plurality of laser beams, in sequence or all at one time, to a plurality of points across the retro-reflective ... |
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| High-Precision Optical Interferometry and Application to Be Stars |
NOV 2004 |
2 pages |
| Authors:
Christopher Tycner; NAVAL OBSERVATORY FLAGSTAFF AZ
|
| This dissertation presents a new technique for calibrating optical long-baseline interferometric observations that are obtained simultaneously in a number of spectral channels. For certain classes of objects such as emission- line sources or binary systems, the new technique allows the calibration corrections and source characteristics to be obtained from the observations of a program star alone. This is because for such sources, the parameters describing the characteristics of the source ... |
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| Resolving the Effects of Rotation in Early Type Stars |
2004 |
9 pages |
| Authors:
Deane M. Peterson; Christian A. Hummel; Thomas Pauls; Thomas Armstrong; James Benson; Charmaine Gilbreath; Robert Hindsley; Donald Hutter; David Mozurkewich; STATE UNIV OF NEW YORK AT STONY BROOK DEPT OF PHYSICS AND ASTRONOMY
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| We review the theory of rotating stars, first developed 80 years ago. Predictions include a specific relation between shape and angular velocity and between surface location and effective temperature and effective gravity. Seen at arbitrary orientation rapidly rotating stars will display ellipsoidal shapes and possibly quite asymmetric intensity distributions. The flattening due to rotation has recently been detected at PTI and VLTI. With the increasing baselines available in the visible ... |
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| Estimation of Fringe Parameters |
2004 |
11 pages |
| Authors:
D. Mozurkewich; J. T. Armstrong; G. C. Gilbreath; T. A. Pauls; NAVAL RESEARCH LAB WASHINGTON DC
|
| In this report we explore replacing the widely used optimal V2 estimator with a model-fitting approach. We show that it is possible to fit the fringe power spectra with a physically reasonable model. This approach eliminates the biggest problem with the standard squared visibility estimator - determining the additive, detector-noise bias. We examine the dependence of the bias on count rate for consistency between on- and off-fringe measurements. The change ... |
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| Smart Sensors Based on Integrated Optics and Microelectromechanical Systems |
21 JUL 2003 |
38 pages |
| Authors:
Tristan J. Tayag; TEXAS CHRISTIAN UNIV FORT WORTH
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| The integration of real-time digital signal processing with sensor technology has spurred a renewed effort for "smart sensors" in military applications. For example, there has been a resurgence in the U.S. Army's interest in low-frequency acoustic sensors for the identification and tracking of targets such as tracked vehicles, airborne vehicles, and munition muzzle blasts. For this particular application, there exists a need for compact, rugged, and very sensitive arrays of ... |
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| MSX In-Band Irradiances Using Stellar Source Functions |
31 MAR 2003 |
|
| Authors:
Shawn Burdick; Thomas Murdock; David Pollock; Ray Russell; FRONTIER TECHNOLOGY INC BEVERLY MA
|
 | Stellar calibration sources play an important role in the on-orbit calibration of IR remote sensing satellites. As ideal point sources against a very low background, they provide an optimal calibration of the point response function of a sensor in the state in which it will make measurements. However, not all stars are constant. Not all stars that have their energy distributions characterized to a few percent from ground-based facilities. Furthermore, ... |
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| Development of an Airborne Integrated Phase Doppler Interferometer/ Imaging Probe for Accurate Cloud Droplet Size Distribution Measurement |
12 NOV 2002 |
38 pages |
| Authors:
William D. Bachalo; Subramanian V. Sankar; ARTIUM TECHNOLOGIES INC SUNNYVALE CA
|
| The Phase I effort investigated the feasibility of developing an optical probe based on phase Doppler interferometry (PDI) for reliable and accurate measurement of the cloud droplet size distribution from airborne platforms. The key features of this device are high accuracy and precision droplet sizing, large dynamic range, accurate concentration measurement throughout the entire instrument dynamic range, very low coincidence errors, and large counting volume. |
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| Multi-Scale Strain Measurements of a Multi-Phase Material |
AUG 2002 |
20 pages |
| Authors:
C. T. Liu; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| New Developments in Atom Interferometry |
13 MAY 2002 |
9 pages |
| Authors:
David Pritchard; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| We have pioneered new measurement techniques using coherent atom optics (such as beam-splitters, mirrors and lenses) to manipulate matter waves. During this grant period we built an improved atom interferometer which splits deBroglie waves of matter into two physically separate paths and then recombines the waves to make interference hinges of matter. Using this apparatus our experiments are extremely sensitive to any forces on the atoms. |
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| Enhanced Doppler Picture Velocimetry (DPV) for Planar Velocity Measurements in High Speed Shock Tunnel Flow |
2002 |
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| Authors:
F. Seiler; A. George; F. Leopold; M. Havermann; J. Srulijes; INSTITUT FRANCO-ALLEMAND DE RECHERCHES SAINT-LOUIS (FRANCE)
|
| A technique for visualizing a velocity field in an entire plane has been developed by taking so-called "Doppler Pictures" using Michelson interferometry. With the Doppler Picture Velocimetry (DPV) information about the instantaneous and local velocities of tracers passing through a light sheet are available. The tracer particles are illuminated by a laser light source and the frequency of the scattered light, in case of moving particles, is shifted by the ... |
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| Coating-Bond Evaluation Using Dispersion Curves and Laser-Ultrasonics |
DEC 2001 |
31 pages |
| Authors:
Agostino Abbate; Bryon Knight; Moayyed A. Hussain; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| The dispersion characteristics of Rayleigh surface waves are used to distinguish the quality of the bond between a coating and the metallic substrate. The velocity versus frequency curves for good or 'welded' bonds differ significantly from the correspondent dispersion curves for poorer or 'smooth' bonds. A theoretical dynamic model of the ultrasonic experiments was developed and compared with experimental results. As examples of welded contacts, we used coatings of tantalum ... |
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| Resaerch Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum |
30 JUN 2001 |
43 pages |
| Authors:
George W. Flynn; Richard M. Osgood Jr.; Louis E. Brus; Tony F. Heinz; Irving P. Herman; TRUSTEES OF COLUMBIA UNIV NEW YORK
|
| Experiments are described that have the goal of understanding the basic physics of quantum confined electronics. In the first experiment new fabrication processes for making GaSb-based quantum dots have been examined. The scientific goal of this work is to develop methods to realize damage free etching of the dots. In the second experiment stepped metal surfaces have been used to measure the scattering cross-sections of electrons at simple features, such ... |
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| Atom Interferometry, Atom Optics and the Atom Laser |
FEB 2001 |
11 pages |
| Authors:
Wolfgang Ketterle; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| Our goal is to pursue atom interferometry and advances of the atom laser using Bose-Einstein condensates. Condensates will be moved from a vacuum chamber where they were produced into a science chamber where a great variety of experiments can be carried out without the severe limitations imposed by the cooling and trapping techniques applied in the first chamber. The new chamber has been constructed, and first Bose-Einstein condensates were produced ... |
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| Development and Testing of the Virginia Tech Doppler Global Velocimeter |
FEB 2001 |
112 pages |
| Authors:
Troy B. Jones; Roger L. Simpson; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE AND OCEAN ENGINEERING
|
| A new laser based flow interrogation system, capable of simultaneous measurement of planar three-component velocity data, was constructed and tested. The Virginia Tech Doppler Global Velocimeter (DGV) system was designed for use in the Virginia Tech Stability Wind Tunnel as a tool for investigating complex three-dimensional separated flow regions. The systems was designed for robustness, ease of use, and for acquisition of low uncertainty velocity data. A series of tests ... |
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| Characteristics of Acoustic Wave Propagation in Dermis for the Diagnosis of the Superficial Tissue Damage in Radiation Therapy |
JUL 2000 |
7 pages |
| Authors:
Chung-Wei Lyu; Hsian-Jenn Wang; Lee-Cheng Peng; Chien Chou; NATIONAL YANG-MING UNIV TAIPEI (TAIWAN)
|
| Measurement of tissue radiation damage quantitatively in radiation therapy is very important to optimize the therapeutic treatment. Ionized radiation induces homogenization of the extracellular matrix which is synthesized by fibroblast and the randoinization of the orientation of the collagen fibers in dermis If the dermis is exposed by ionized radiation, a thermal acoustic shear wave which propagates in dermis becomes harmonic wave; Otherwise an inharmonic wave is expected because of ... |
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| Adapter for Objective Lens of an Optical Instrument |
13 JUN 2000 |
10 pages |
| Authors:
Ted J. Gross; Paul C. Schreck; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
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| An adapter is disclosed for operatively mating an optical laser interference filter with an objective lens of night vision goggles, without causing an incompatibility between the night vision goggles and the Gideon NVG Head Up Display. |
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| Amplitude and Temporal Jitter Associated with the NPS Active Mode-LockedSigma Laser |
JUN 2000 |
83 pages |
| Authors:
James A. Anderson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Electro-optic techniques for analog-to-digital conversion (ADC) are being developed for wideband signal collection and analysis. They have the capability of being used for direct signal reception and ADC at an antenna. A fundamental requirement for these designs is a high-frequency optical pulse train with uniform amplitude and pulse spacing. A mode-locked fiber laser can provide pulse rates and pulse widths suitable for these high bandwidth ... |
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| Ultra-Fast Optical Signal Encoding and Analysis for Communications and Data Fusion Networks |
01 MAY 2000 |
59 pages |
| Authors:
David J. Brady; James J. Coleman; Kenneth G. Purchase; ILLINOIS UNIV AT URBANA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| We describe the distributed Bragg pulse shaper, the quantum dot spectrometer and interferometric imaging systems developed under this program. The distributed Bragg pulse shaper is a series of partially reflecting Bragg mirrors constructed over an integrated optical waveguide. Through parallel electrical modulation of the Bragg mirror resonances one can encode terahertz bandwidth optical signals with this device. Quantum dot detectors and interferometric sensors ... |
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| Surface Fatigue Lives of Case-Carburized Gears With an Improved Surface Finish |
APR 2000 |
15 pages |
| Authors:
T. L. Krantz; M. P. Alanou; H. P. Evans; R. W. Snidle; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 9310 steel gears was provided with a near-mirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were determined using data from metrology, profilometry, and interferometric microscope ... |
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| Coated Fiber Pressure Sensors Utilizing Pressure Release Coating Material |
24 MAR 2000 |
22 pages |
| Authors:
Anthony Dandridge; Alan B. Tveten; Sandeep T. Vohra; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This invention pertains to a sensor comprising of glass optical fiber, a cellular pressure release material surrounding the fiber, and means for determining responsivity of the sensor, the sensor having responsivity of at least about -160 dB re rad/m-mu-Pa, which corresponds to sensitivity of about 50 times better than prior art. The sensor can be made part of an optical interferometer which is characterized by splitting of an entering light ... |
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| Interferometric Measurement with Squeezed Light |
03 MAR 2000 |
9 pages |
| Authors:
Hermann A. Haus; Erich P. Ippen; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| The main goal of our research is the achievement of substantial squeezing of the vacuum fluctuations associated with a soliton. If the soliton is injected into the probe port of a Mach-Zehnder interferometer and the squeezed vacuum is injected into the vacuum port, sub-shot noise measurements of the phase difference between the two arms of the interferometer can be performed. The soliton squeezing is being done ... |
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| Compact Autonomous Measuring System for Large Membrane Mirror |
MAR 2000 |
32 pages |
| Authors:
Vadim A. Parfenov; STATE OPTICAL INST LENINGRAD (USSR)
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| Principal and functional schematics of a liquid-crystal (LC) Hartmann wavefront sensor and two-wavelength dynamic holographic interferometer capable of measuring severe aberrations up to 2000 micrometers are proposed. The LC hartmann sensor can be implemented in different versions including Shack LC lenslet array, large focusing LC tunable lens or LC hole array. The simplest controllable LC hole array was manufactured and is under calibration at the ... |
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| Numerical Data-Processing Simulation of Microarcsecond Classical and Relativistic Effects in Space Astrometry |
MAR 2000 |
8 pages |
| Authors:
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| The accuracy of astrometric observations conducted via a space-borne optical interferometer orbiting the Earth is expected to approach a few microarcseconds. Data processing of such extremely high-precision measurements requires access to a rigorous relativistic model of light ray propagation developed in the framework of General Relativity. The data processing of the space interferometric observations must rely upon the theory of general- relativistic transformations among the spacecraft, geocentric, and solar barycentric ... |
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| Optical Field Reconstruction Using Phase-Space Tomography |
21 DEC 1999 |
3 pages |
| Authors:
Michael G. Raymer; OREGON UNIV EUGENE DEPT OF PHYSICS
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| Measurement of light transport in a random, multiple scattering medium can provide details about the spatial structure of inhomogeneities within the medium. Progress made includes construction of a new system for making measurements of the complex, two-point optical field correlation function for continuous-wave laser light after propagating through a random-dielectric medium, in particular polystyrene spheres in water. The new system is based on a Sagnac shearing ... |
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| Adaptive Polarization Diversity Detection Scheme for Coherent Communications and Interferometric Fiber Sensors |
16 NOV 1999 |
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| Authors:
Alan D. Kersey; Michael J. Marrone; Anthony Dandridge; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A method and apparatus for overcoming polarization induced signal fading in both heterodyne communication and interferometric sensing. An adjustable birefringent element in series with a linear-polarization beam splitter forms an elliptical-polarization beam splitter. The birefringent element controllably evolves the states of polarization of two input signals thereby controlling the power contribution of each signal onto the orthogonal axes used by the linear beam splitter. When the states of polarization are ... |
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OPTICAL INTERFEROMETERS
