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Thermal images model the long-infrared range of the electromagnetic spectrum and provide meaningful information even when there is no visible illumination. Yet, unlike imagery that represents radiation from the visible continuum, infrared…

Image and Video Processing · Electrical Eng. & Systems 2021-08-03 Nolan B. Gutierrez , William J. Beksi

We demonstrate a technique for obtaining the density of atomic vapor, by doing a fit of the resonant absorption spectrum to a density-matrix model. In order to demonstrate the usefulness of the technique, we apply it to absorption in the…

Atomic Physics · Physics 2017-06-15 Harish Ravi , Mangesh Bhattarai , Vasant Natarajan

Infra-red (IR) thermography is an essential diagnostic tool for understanding the edge plasma behavior in fusion devices. In this work, we present a new in-house numerical tool, Functional Analysis of Heat Flux (FAHF), for IR thermographic…

Accurate thermal modeling of Terminal Test Masses (TTMs) is crucial for optimizing the sensitivity of gravitational wave interferometers like Virgo. In fact, in such gravitational wave detectors even minimal laser power absorption can…

We present new images and continuum spectral analysis for 14 resolved Galactic SNRs selected from the 74 MHz Very Large Array Low-Frequency Sky Survey Redux (VLSSr). We combine new integrated measurements from the VLSSr with flux densities…

High Energy Astrophysical Phenomena · Physics 2021-09-15 G. Castelletti , L. Supan , W. M. Peters , N. E. Kassim

Transient absorption is a very powerful observable in attosecond experiments on atoms, molecules and solids and is frequently used in experiments employing phase-locked few-cycle infrared and XUV laser pulses derived from high harmonic…

Atomic Physics · Physics 2020-08-26 Lorenz Drescher , Marc J. J. Vrakking , Jochen Mikosch

Optical characterization of AlGaAs microdisk resonant cavities with a quantum dot active region is presented. Direct passive measurement of the optical loss within AlGaAs microdisk resonant structures embedded with InAs/InGaAs…

We present the first two-dimensional (2D) optical Thomson scattering measurements of electron density and temperature in laser-produced plasmas. The novel instrument directly measures $n_e(x,y)$ and $T_e(x,y)$ in two dimensions over large…

Instrumentation and Detectors · Physics 2023-09-12 H. Zhang , J. J. Pilgram , C. G. Constantin , L. Rovige , P. V. Heuer , S. Ghazaryan , M. Kaloyan , R. S. Dorst , D. B. Schaeffer , C. Niemann

A tunable diode laser spectrometer has been employed to examine the overtone absorption lines of $^{12}$CH$_4$ in the region around 12780 cm$^{-1}$ (780 nm) at room temperature. The spectrometer sources are commercially available tunable…

Chemical Physics · Physics 2022-02-10 A. Lucchesini

We describe the design of a Thomson scattering (TS) diagnostic to be used on the SMall Aspect Ratio Tokamak (SMART). SMART is a spherical tokamak being commissioned in Spain that aims to explore positive triangularity (PT) and negative…

We demonstrate Doppler-free saturated absorption spectroscopy of cold molecular radicals formed by laser ablation inside a cryogenic buffer gas cell. By lowering the temperature, congested regions of the spectrum can be simplified, and by…

Diffusing wave spectroscopy (DWS) can be employed as an optical rheology tool with numerous applications for studying the structure, dynamics and linear viscoelastic properties of complex fluids, foams, glasses and gels. To carry out DWS…

Soft Condensed Matter · Physics 2018-11-06 Chi Zhang , Mathias Reufer , Danila Gaudino , Frank Scheffold

We present deep GMRT 21cm absorption spectra of 10 damped Lyman-$\alpha$ systems (DLAs), of which 8 are at redshifts $z \ga 1.3$. HI absorption was detected in only one DLA, the $z = 0.5318$ absorber toward PKS 1629+12, which has been…

Astrophysics · Physics 2008-11-26 Nissim Kanekar , Jayaram N Chengalur

Cubic boron arsenide (BAs) is attracting greater attention due to the recent experimental demonstration of ultrahigh thermal conductivity \k{appa} above 1000 W/mK. However, its bandgap has not been settled and a simple yet effective method…

We present a detailed study of the HI 21cm absorption system at z=0.0912 towards the radio quasar B0738+313. The uncommonly narrow main absorption line and weak secondary line are resolved for the first time. In addition we find it…

Astrophysics · Physics 2009-10-31 W. M. Lane , F. H. Briggs , A. Smette

Stellar seismology reveals some interior properties of thousands of solar-type stars but the solar seismic sound speed stays puzzling since a decade as it disagrees with the Standard Solar Model (SSM) prediction. One of the explanations of…

Solar and Stellar Astrophysics · Physics 2015-09-14 M. Le Pennec , X. Ribeyre , J. -E. Ducret , S. Turck-Chièze

We have used the Green Bank Telescope (GBT) and Berkeley-Illinois-Maryland Association (BIMA) array to search for redshifted millimetre absorption in a sample of damped Lyman-alpha absorption systems (DLAs). This brings the number of…

Astrophysics · Physics 2009-11-10 S. J. Curran , M. T. Murphy , Y. M. Pihlstroem , J. K. Webb , A. D. Bolatto , G. C. Bower

We report results from a deep search for redshifted HI 21cm absorption from eight damped Lyman-$\alpha$ absorbers (DLAs) detected in our earlier optical survey for DLAs towards radio-loud quasars. HI 21cm absorption was detected from the $z…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Nissim Kanekar , Sara L. Ellison , Emmanuel Momjian , Brian A. York , Max Pettini

We present DARTR: a Data Adaptive RKHS Tikhonov Regularization method for the linear inverse problem of nonparametric learning of function parameters in operators. A key ingredient is a system intrinsic data-adaptive (SIDA) RKHS, whose norm…

Machine Learning · Statistics 2022-03-09 Fei Lu , Quanjun Lang , Qingci An

We study the physical properties of the Lyman-alpha forest by applying the inversion method described by Pichon et al. (2001) to the high resolution and high S/N ratio spectrum of the z_em=2.40 quasar HE 1122-1628 obtained during Science…

Astrophysics · Physics 2009-11-06 E. Rollinde , P. Petitjean , C. Pichon