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We study modulation spectroscopy of the potassium D2 transitions at 766.7 nm. The vapour pressure, controlled by heating a commercial reference cell, is optimized using conventional saturated absorption spectroscopy. Subsequent heterodyne…

Atomic Physics · Physics 2012-05-03 L. Mudarikwa , K. Pahwa , J. Goldwin

We use a newly commissioned rapid expansion aerosol chamber (REACh) facility to study the homogeneous nucleation of water vapor to form liquid droplets. We perform high-speed measurements to track the partitioning of water into vapor and…

Thermal mode spectroscopy (TMS) has been recently proposed for accurately measuring thermal diffusivity of solids from a temperature decay rate of a specific thermal mode selected by three- dimensional (anti)nodal information [Phys. Rev.…

Materials Science · Physics 2018-06-29 Hideshi Ishida , Hirotsugu Ogi

The interaction between off-resonant laser pulses and excitons in monolayer transition metal dichalcogenides is attracting increasing interest as a route for the valley-selective coherent control of the exciton properties. Here, we extend…

The Two-Photon Absorption (TPA) process provides an excellent method for the characterisation of solid-state sensors due to its intrinsic 3D resolution for the excitation of electron-hole pairs. This paper presents the commissioning of a…

2D profiles of electron density and neutral temperature are inferred from multi-delay Coherence Imaging Spectroscopy data of divertor plasmas using a non-linear inversion technique. The inference is based on imaging the spectral…

In this paper, we describe an experiment performed at the Laboratoire de Physique des Lasers and dedicated to an optical measurement of the Boltzmann constant. With the proposed innovative technique, determining comes down to an ordinary…

Coherent anti-Stokes Raman Spectroscopy (CARS) is a laser-based measurement technique widely applied across many science and engineering disciplines to perform non-intrusive gas diagnostics. CARS is often used to study combustion, where the…

Machine Learning · Computer Science 2022-05-25 Gregory J. Hunt , Cody R. Ground , Andrew D. Cutler

A switching-off process very similar to those in real high-voltage self-blast circuit-breakers is emulated in a model chamber to study the arc properties by optical emission spectroscopy. The arc is operated in a chamber filled with SF$_6$…

High-resolution observations of the solar chromosphere at millimeter wavelengths are now possible with the Atacama Large Millimeter Array (ALMA), promising to tackle many open problems in solar physics. Observations from other ground and…

Solar and Stellar Astrophysics · Physics 2018-12-12 João M. da Silva Santos , Jaime de la Cruz Rodríguez , Jorrit Leenaarts

The Tianlai cylinder pathfinder is a radio interferometer array to test 21 cm intensity mapping techniques in the post-reionization era. It works in passive drift scan mode to survey the sky visible in the northern hemisphere. To deal with…

Instrumentation and Methods for Astrophysics · Physics 2024-12-10 Kaifeng Yu , Shifan Zuo , Fengquan Wu , Yougang Wang , Xuelei Chen

This paper presents a spectra normalization method for laser-induced breakdown spectroscopy (LIBS) measurements by converting the recorded characteristic line intensity at varying conditions to the intensity under a standard condition with…

Plasma Physics · Physics 2015-05-28 Zhe Wang , Lizhi Li , Logan West , Zheng Li , Weidou Ni

Spontaneous Raman spectroscopy (SRS) is a conventional in-situ laser diagnostic method that has been widely used for measurements of temperature and major species. However, SRS in sooting flames suffers from strong interference including…

Optics · Physics 2023-02-15 Hu Meng , Yihua Ren , Heinz Pitsch

We consider the inverse source problem of thermo- and photoacoustic tomography, with data registered on an open surface partially surrounding the source of acoustic waves. Under the assumption of constant speed of sound we develop an…

Analysis of PDEs · Mathematics 2020-04-17 Mtthias Eller , Philip Hoskins , Leonid Kunyansky

We consider a two-color formaldehyde PLIF thermometry scheme using a wavelength-switching injection seeding Nd:YAG laser at 355 nm. The 28183.5 cm-1 and 28184.5 cm-1 peaks of formaldehyde are used to measure low temperature combustion zone.…

Optics · Physics 2024-10-01 Xunchen Liu , Yayao Wang , Zhen Wang , Fei Qi

We report Giant Metrewave Radio Telescope (GMRT) 21cm observations of two confirmed and one candidate low redshift damped Lyman-alpha systems (DLAS). HI absorption was detected in the two confirmed systems, at z=0.2378 and z=0.5247, with…

Astrophysics · Physics 2009-11-06 Nissim Kanekar , Jayaram N. Chengalur

We describe an optical method to directly measure position-dependent thermal diffusivity of reflective single crystal samples across a broad range of temperatures for condensed matter physics research. Two laser beams are used, one as a…

In this paper, we present the latest results on the measurement of the Boltzmann constant kB, by laser spectroscopy of ammonia at 10 ?m. The Doppler absorption profile of a ro-vibrational line of an NH3 gas sample at thermal and pressure…

The development of systems to measure and optimize emerging energetic material performance is critical for CWA defeat. This study documents a combination of two spectroscopic systems designed to monitor decomposition of a CWA simulant and…

Instrumentation and Detectors · Physics 2024-12-05 Preetom Borah , Milad Alemohammad , Mark Foster , Timothy P. Weihs

The development of advanced diagnostic systems to measure and optimize emerging energetic material performance is critical for the defeat of Chemical Warfare Agents (CWA). This study presents an integrated multi-spectroscopic approach to…

Chemical Physics · Physics 2026-01-01 Preetom Borah , Elif Irem Senyurt , Rohit Berlia , Jesse Grant , Edward Dreizin , Timothy P Weihs