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Results for “INTERFEROMETRY”

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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Multipoint sensing with a low-coherence source using single-arm frequency-shifted interferometry

We demonstrate that multiple-site sensing along an optical fiber can be done with incoherent continuous-wave light. Here, using a broadband low-coherence noise source, a slow detector, and an optical modulator, we construct a single-arm frequency-shifted interferometer (SA-FSI) capable of simultaneously sensing multiple weak-reflection sites distributed either in parallel or in series along fiber links. By scanning the driving frequency of an electro-optic amplitude modulator in the range of 2.7–3.2 GHz at steps of 41.7 KHz, we demonstrate a spatial resolution of 0.3 m and a measurement range of over 1 km.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Spectral phase coherence in HOM interferometry

We examine the role of spectral phase in Hong-Ou-Mandel interference by comparing interferograms for pure and mixed states. We find that HOM interference cannot be taken as a signature of coherent frequency superpositions.

Lingaraju, Navin↗
DOE OSTI2022

Cross-polarized common-path temporal interferometry for high-sensitivity strong-field ionization measurements

Absolute density measurements of low-ionization-degree or low-density plasmas ionized by lasers are very important for understanding strong-field physics, atmospheric propagation of intense laser pulses, Lidar etc. A cross-polarized common-path temporal interferometer using balanced detection was developed for measuring plasma density with a sensitivity of ∼0.6 mrad, equivalent to a plasma density-length product of ∼2.6 × 10 13 cm −2 if using an 800 nm probe laser. By using this interferometer, we have investigated strong-field ionization yield versus intensity for various noble gases (Ar, Kr, and Xe) using 800 nm, 55 fs laser pulses with both linear (LP) and circular (CP) polarization. The experimental results were compared to the theoretical models of Ammosov-Delone-Krainov (ADK) and Perelomov-Popov-Terent’ev (PPT). We find that the measured phase change induced by plasma formation can be explained by the ADK theory in the adiabatic tunneling ionization regime, while PPT model can be applied to all different regimes. We have also measured the photoionization and fractional photodissociation of molecular (MO) hydrogen. By comparing our experimental results with PPT and MO-PPT models, we have determined the likely ionization pathways when using three different pump laser wavelengths of 800 nm, 400 nm, and 267 nm.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

High-harmonic spin-shearing interferometry for spatially resolved EUV magneto-optical spectroscopy

We present a method for achieving hyperspectral magnetic imaging in the extreme ultraviolet (EUV) region based on high-harmonic generation (HHG). By interfering two mutually coherent orthogonally-polarized and laterally-sheared HHG sources, we create an EUV illumination beam with spatially-dependent ellipticity. By placing a magnetic sample in the beamline and sweeping the relative time delay between the two sources, we record a spatially resolved interferogram that is sensitive to the EUV magnetic circular dichroism of the sample. This image contains the spatially-resolved magneto-optical response of the sample at each harmonic order, and can be used to measure the magnetic properties of spatially inhomogeneous magnetic samples.

Optics↗
DOE OSTI2016

Develop Prototype Microwave Interferometry Diagnostic

A prototype microwave interferometer was created at NSTec to characterize moving conductive fronts in upcoming experiments. The interferometer is capable of operation in the ~26-40 GHz band, and interrogating fronts with more than 1 W of power.

42 ENGINEERING↗
DOE OSTI2019

Swept-Frequency Acoustic Interferometry (SFAI) and Related Technologies

Researchers at Los Alamos National Lab have developed acoustic technologies to accurately discern the characteristics of materials within closed containers non-invasively. SFAI and related technologies use high-frequency sound to characterize liquids, gasses, mixtures, emulsions, and other fluids inside pipes and containers. SFAI offers the potential to measure material characteristics and two-and three-phase flows within pipes including flow rates and water- and gas-volume fractions all with a small-footprint device. SFAI is an enabling component of a 2014 R&D 100 Award Winner.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Investigation of Radius of Curvature Measurements using Laser Interferometry [Slides]

Goals for this work are to: develop an application using a ZYGO Verifire for calibration of artifacts where the measurand is defined as a Radius of Curvature (ROC), validate the measurements through an uncertainty analysis, and determine if the calibration method is a viable alternative/option for calibration outside of current standard methodologies.

42 ENGINEERING↗