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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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Here, we discuss a project to develop a precision metrology system for variable-line-spacing x-ray gratings using interferometric microscopes. We are developing test standards and calibration techniques to measure and correct for geometrical distortion and blur, and data processing techniques to combine multiple measurements and measure line spacing with high accuracy.
The Micro Arcsecond Metrology Testbed (MAM) is a laboratory-based, long baseline, white-light interferometer inside a vibration-isolated vacuum tank.
Going beyond the standard quantum limit in noisy quantum metrology is an important and challenging task. Here we show how Dicke states can be used to surpass the standard quantum limit and achieve the Heisenberg limit in open quantum systems. The system we study has qubits symmetrically coupled to a resonator, and our objective is to estimate the coupling between the qubits and the resonator. The time-dependent quantum Fisher information with respect to the coupling is studied for this open quantum system where the same decay rates are assumed on all qubits. We show that when the system is initialized to a Dicke state with an optimal excitation number one can go beyond the standard quantum limit and achieve the Heisenberg limit even for finite values of the decays on the qubit and the resonator, particularly when the qubits and resonator are strongly coupled. We compare our results against the highly entangled GHZ state and a completely separable state and show that the GHZ state performs quite poorly, whereas under certain noise conditions the separable state is able to go beyond the standard quantum limit due to subsequent interactions with a resonator.
Quantum entanglement and coherence often allow for protocols that outperform classical ones in estimating a system’s parameter. When using infinite-dimensional probes (such as a bosonic mode), one could, in principle, obtain infinite precision in a finite time for both classical and quantum protocols, which makes it hard to quantify potential quantum advantage. However, such a situation is unphysical, as it would require infinite resources, so one needs to impose some additional constraint: typically the average energy employed by the probe is finite. Here we treat both energy and time as a resource, showing that, in the presence of noise, there is a nontrivial interplay between the average energy and the time devoted to the estimation. Our results are valid for the most general metrological schemes (e.g., adaptive schemes, which may involve entanglement with external ancillae or any kind of continuous measurement). We apply recently derived precision bounds for all parameters characterizing the paradigmatic case of a bosonic mode, subject to Lindbladian noise. We show how the time employed in the estimation should be partitioned in order to achieve the best possible precision. In most cases, the optimal performance may be obtained without the necessity of adaptivity or entanglement with ancilla. We compare results with classical strategies. Interestingly, for temperature estimation, applying a fast-prepare-and-measure protocol with Fock states provides better scaling with the number of photons than any classical strategy.
The TREAT Reactor Metrology (RMet) program provides value through the post-irradiation gamma spectroscopy of flux and fission wires.
Metrology requirements for Apollo project, noting control and measuring equipment and calibration procedures
We describe the Metrology System for NASA's StarLight mission, a space-based separated-spacecraft stellar interferometer.
A facility to test the linearity and drift of heterodyne laser metrology gauges for measuring distances of 1 to 7 meters with 10 picometer repeatability is described.
This paper discusses the techniques for the reduction of cyclic errors in laser metrology gauges for the space interferometry mission.
Describes a metrology subsystem for NASA's Starlight mission, a space-based separated-spacecraft stellar interferometer.
In this paper, the metrology pointing sensor of the Starlight ground instrument prototype is characterized and a siderostat pointing control loop is closed between two optical benches with a 10 meter separation.
The Space Interferometry Mission (SIM) relies on interferometry and metrology capable of measuring the change in the optical path difference with picometer accuracy.
An assessment of the inflight performance of the Shuttle Radar Topography Mission (SRTM) Metrology System, also known as the Attitude and Orbit Determination avionics (AODA), is presented. The assessment is based on analysis of raw sensor data obtained during the mission.
This paper provides a description of the metrology camera, the process used to prepare it for flight on SRTM, the LED target development effort, test and alignment issues, and the observed in-flight performance.
We present an auto-calibration and metrology system concept to correct for phase errors and mechanical deformation during the misssion.
This paper describes heterodyne displacement metrology gauge signal processing methods that achieve satisfactory robustness against low signal strength and spurious signals, and good long-term stability. We have a proven displacement-measuring approach that is useful not only to space-optical projects at JPL, but also to the wider field of distance measurements.
The Space Interferometry Mission (SIM), Terrestrial Planet Finder (TPF) and James Web Space Telescope (JWST) need stable, reliable distance metrology with subnanometer accuracy.
We provide and overview of the developments in the field of high-accuracy absolute optical metrology with emphasis on space-based applications. Specific work on the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor is described along with novel applications of the sensor.