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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.

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At least 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

The Laser Interferometer Space Antenna: Unveiling the Millihertz Gravitational Wave Sky

The first terrestrial gravitational wave interferometers have dramatically underscored the scientific value of observing the Universe through an entirely different window, and of folding this new channel of information with traditional astronomical data for a multimessenger view. The Laser Interferometer Space Antenna (LISA) will broaden the reach of gravitational wave astronomy by conducting the first survey of the millihertz gravitational wave sky, detecting tens of thousands of individual astrophysical sources ranging from white-dwarf binaries in our own galaxy to mergers of massive black holes at redshifts extending beyond the epoch of reionization. These observations will inform - and transform - our understanding of the end state of stellar evolution, massive black hole birth, and the co-evolution of galaxies and black holes through cosmic time. LISA also has the potential to detect gravitational wave emission from elusive astrophysical sources such as intermediate-mass black holes as well as exotic cosmological sources such as inflationary fields and cosmic string cusps.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Two-dimensional second harmonic dispersion interferometer

An interferometer having a fundamental beam generator, a first second harmonic generator, a waveplate, a second second harmonic generator, a harmonic separator, and a polarizing beam splitter, mounted uniaxially, (i.e., the components are aligned along one optical axis), wherein the interferometer is adapted to change a diameter of a beam to match a diameter of a sample, and to change the diameter of the beam back to its original diameter.

Wessel, Frank Joseph↗
DOE OSTI2022

Multi-axis Accelerometry and Rotation Sensing using a Point Source Atom Interferometer

A point source atom interferometer (PSI) is a device where atoms are split and recombined by applying a temporal sequence of Raman pulses during the expansion of a cloud of cold atoms behaving approximately as a point source. Unlike a conventional light pulse atom interferometer, the PSI can produce a signal that corresponds to multi-axis rotation only, independent of acceleration. In addition, it can be used to measure acceleration along one direction, independent of rotation. Here, we describe a modified PSI that can be used to measure multi-axis rotation and multi-axis acceleration. Specifically, this type of PSI can be used to measure two-axes rotation around the directions perpendicular to the light pulses, as well as the acceleration in all three directions, with only one pair of Raman beams. Using two pairs of Raman beams in orthogonal directions sequentially, such a scheme would enable the realization of a complete atom interferometric inertial measurement unit.

Li, Jinyang↗
NASA NTRS2003

The Fizeau Interferometer Testbed

The Fizeau Interferometer Testbed (FIT) is a collaborative effort between NASA's Goddard Space Flight Center, the Naval Research Laboratory, Sigma Space Corporation, and the University of Maryland. The testbed will be used to explore the principles of and the requirements for the full, as well as the pathfinder, Stellar Imager mission concept. It has a long term goal of demonstrating closed-loop control of a sparse array of numerous articulated mirrors to keep optical beams in phase and optimize interferometric synthesis imaging. In this paper we present the optical and data acquisition system design of the testbed, and discuss the wavefront sensing and control algorithms to be used. Currently we have completed the initial design and hardware procurement for the FIT. The assembly and testing of the Testbed will be underway at Goddard's Instrument Development Lab in the coming months.

OPTICS DESIGN↗
NASA NTRS2002

Performance and verification of the Keck Interferometer fringe detection and tracking system

We briefly discuss the instrument design of the Keck Interferometer from a hardware and realtime controls standpoint. We also show some recent visibility data from the instrument and summarize Fatcat's limiting sensitivity. Finally, we will discuss near and longterm evolution of the instrument through planned upgrades and summarize avenues for enhanced capability.

stellar↗
NASA NTRS1998

Unequal-Arms Michelson Interferometers

Michelson interferometers allow phase measurements many orders of magnitude below the phase stability of the laser light injected into their two almost equal-length arms.

Gravitational↗
DOE OSTI2012

On-chip Optical Filters with Designable Characteristics Based on an Interferometer with Embedded Silicon Photonic Structures

We demonstrate chip-scale flat-top filters at near-IR wavelengths using negative index photonic crystal based Mach-Zehnder interferometers. Supported by full three-dimensional numerical simulations, we experimentally demonstrate a new approach for engineering high-pass, low-pass, bandpass, and band-reject filters, based on designing the photonic band diagram both within the bandgap frequency region and away from it. We further show that our approach can be used to design filters that have tunable multilevel response for different sections of the spectrum and for different polarizations. This configuration enables deterministic control of the bandwidth and the rejection ratio of filters for integrated photonic circuits.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Polarisation non-reciprocity cancelling in Sagnac fibre ring interferometer: an attempt of realistic study

Polarisation non-reciprocity (PNR) of Sagnac fibre ring interferometer (FRI) is one the fundamental limits of its long term bias stability. PNR value, being huge initially, then was reduced strongly, but after that PNR problem was left far from PNR cancelling. The latter may be defined as PNR reducing up to 10{sup −10} deg/h when it does not prevent detecting the general relativistic Lense–Thirring effect. Clearly, such PNR cancelling may be treated only theoretically at this point. In this case, one has to model all practical defects of FRI. Present paper describes such kind of study for FRI of commercial fibre optic gyro implementing medium quality components. It is shown that for PNR cancelling, several meters fibre polariser is enough, despite of the stringent limitations of its standard polarisation extinction ratio. Also, a complete FRI configuration is treated for the first time in available literature, including an imperfect fibre coupler. This yields one more PNR component which is non-zero even for completely unpolarised light and which can be effectively suppressed by the fibre polariser too.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Multiwavelength erbium-doped fiber laser based on a polarization-dependent in-line Mach–Zehnder interferometer

A multiwavelength erbium-doped fiber laser based on a polarization-dependent in-line Mach–Zehnder Interferometer (in-line MZI) is proposed and experimental demonstrated. The polarization-dependent in-line MZI demonstrated is constructed by sandwiching a length of polarization maintaining fiber (PMF) between two abrupt fiber tapers fabricated in SMF. The proposed in-line MZI can work as a cost-effective all-fiber-based polarizer. In combination with the nonlinear polarization rotation technique, stable multiwavelength laser comb with uniform wavelength spacing is achieved at room temperature. The wavelength spacing is 0.8 nm. By properly tuning the PCs, the output laser combs with double and triple channel spacing can be also obtained.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Waveform modelling for the Laser Interferometer Space Antenna

LISA, the Laser Interferometer Space Antenna, will usher in a new era in gravitational-wave astronomy. As the first anticipated space-based gravitational-wave detector, it will expand our view to the millihertz gravitational-wave sky, where a spectacular variety of interesting new sources abound: from millions of ultra-compact binaries in our Galaxy, to mergers of massive black holes at cosmological distances; from the early inspirals of stellar-mass black holes that will ultimately venture into the ground-based detectors’ view to the death spiral of compact objects into massive black holes, and many sources in between. Central to realising LISA’s discovery potential are waveform models, the theoretical and phenomenological predictions of the pattern of gravitational waves that these sources emit. This White Paper is presented on behalf of the Waveform Working Group for the LISA Consortium. It provides a review of the current state of waveform models for LISA sources, and describes the significant challenges that must yet be overcome.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Adiabatic Mach–Zehnder interferometer in a dipolar spin-1 condensate

We propose and analyze a realizable scheme for performing a Heisenberg-limited Mach–Zehnder interferometry with a dipolar spin-1 condensate. Based upon adiabatic processes of sweeping the transverse magnetic field, we demonstrate a perfect phase transition, which accomplishes the beam splitter, phase shifter and recombiner as for a Mach–Zehnder interferometer. The attractive dipolar interaction ensures the existence of a path-entangled state which enhances the phase measurement precision to the Heisenberg limit. We also study the spin squeezing of the state generated in the beam splitter and show that the spin squeezing exhibits an extremum near the critical point of phase transition.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

A metal-ceramic coaxial cable with multipoint Fabry-Pérot interferometers for monitoring distributed high temperature

A metal ceramic coaxial cable (MCCC) sensor containing multiple Fabry-Pérot interferometers (FPIs) has been designed, fabricated, and evaluated for measuring distributed high temperatures. The MCCC sensor demonstrated here consists of stainless steel tube and wire conductors, alumina tube insulator, and three pairs of air gap reflectors distributed along the cable. The multipoint sensor operation is realized by the joint time-frequency domain technique, which combines the functions of time-domain reflectometry and frequency division multiplexing to enable the measurement of spatially distributed temperature. The 3-point MCCC-FPI sensor has been demonstrated for distributed temperature measurements between 250 and 550 °C and operability up to 1000 °C. The sensor offers high sensitivity of >0.18 MHz/°C with a measurement resolution of 1 Hz and reasonably small high temperature measurement error range of ±3 °C.

42 ENGINEERING↗
DOE OSTI2017

A metal-ceramic coaxial cable Fabry-Pérot microwave interferometer for monitoring fluid dielectric constant

We report a metal-ceramic coaxial cable Fabry-Pérot interferometer (MCCC-FPI) has been developed as a new microwave sensor and demonstrated for fast and reliably measuring and continuously monitoring dielectric constants for pure and mixed liquids. The sensor only requires a simple reference scan of the interferogram for the FPI with its sensing chamber filled with air or under vacuum to determine the actual inter-reflector length. The sensor is validated by measuring room temperature dielectric constant (εr) at high frequencies around 1.4–4.7 GHz for three vegetable oils (corn, sesame, and olive), the synthetic Mobil ® -1 engine oil, and mixtures containing sesame oil and water. The sensor has been also successfully demonstrated for determining εr values for the Mobil-1 oil at various temperatures and for the well-dispersed sesame oil-water mixtures of different compositions. The Bottcher’s model of effective medium theory is shown to be better suited for predicting the ε r of the sesame oil-water mixture than the Maxwell-Garnett and Bruggeman equations of spherical solutions.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Multiplexable intrinsic Fabry-Pérot interferometers inscribed by femtosecond laser for vibration measurement in high temperature environments

This article reports fabrication technique and demodulation algorithm developments to use multiplexable intrinsic Fabry-Pérot interferometer (IFPI) fiber sensor array for distributed vibration measurements at high temperatures. Using femtosecond laser direct writing scheme, IFPI array were fabricated through laser-induced Type II scattering points in single mode fiber cores. Reflection spectra of IFPI array were demodulated in real-time using modified Bunemen frequency analysis. The demodulation algorithm, which was implemented using a photodetector-array spectrometer, achieves 64-nε dynamic strain resolution at 1-kHz spectral acquisition rate and 2-kHz maximum vibration bandwidth. Performance and stabilities of IFPI sensor array were characterized from room temperatures to 800 °C. The static strain resolution was 0.6 με and the minimum detectable dynamic strain amplitude was 23 nε/√Hz at 800 °C. The multiplex performance was also tested by measuring dynamic strain in time domain through six IFPI sensor array fabricated in one fiber. This paper presents an integrated and low-cost sensing solution to perform distributed vibration measurements in harsh environments.

42 ENGINEERING↗
DOE OSTI2016

The implementation and data analysis of an interferometer for intense short pulse laser experiments

We present an interferometry setup and the detailed fringe analysis method for intense short pulse (SP) laser experiments. The interferometry scheme was refined through multiple campaigns to investigate the effects of pre-plasmas on energetic electrons at the Jupiter Laser Facility at Lawrence Livermore National Laboratory. The interferometer used a frequency doubled ( ${\it\lambda}=0.527~{\rm\mu}\text{m}$ ) 0.5 ps long optical probe beam to measure the pre-plasma density, an invaluable parameter to better understand how varying pre-plasma conditions affect the characteristics of the energetic electrons. The hardware of the diagnostic, data analysis and example data are presented. Here, the diagnostic setup and the analysis procedure can be employed for any other SP laser experiments and interferograms, respectively.

42 ENGINEERING↗
DOE OSTI2011

Plasmonic optical switches based on Mach-Zender interferometer

Electro-optical switches composed of two Mach-Zehnder interferometer waveguides filled with 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) have been proposed and investigated. The characteristics of the switch waveguide are analyzed. The finite-difference time domain simulation results reveal that the structure can operate as an optical switch by controlling the voltage V{sub 1} or V{sub 2} applied on the region filled with the DAST material with the {pi} phase shift voltage as V{sub {pi}} = 2.9 V. The structure has a small dimension of hundreds of nanometers.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗