scholarly journals Dual-laser wavelength Thomson scattering at Wendelstein 7-X

2018 ◽  
Vol 89 (10) ◽  
pp. 10C115 ◽  
Author(s):  
E. Pasch ◽  
M. N. A. Beurskens ◽  
S. A. Bozhenkov ◽  
G. Fuchert ◽  
R. C. Wolf ◽  
...  
Keyword(s):  
Thomson Scattering ◽  
Laser Wavelength ◽  
Dual Laser

Dual-laser, self-calibrating Thomson scattering measurements in RFX-mod

2017 ◽  
Vol 59 (5) ◽  
pp. 055021 ◽  
Author(s):  
O McCormack ◽  
L Giudicotti ◽  
A Fassina ◽  
R Pasqualotto
Keyword(s):  
Thomson Scattering ◽  
Scattering Measurements ◽  
Dual Laser

On combining the beam path of similar wavelength lasers for dual-laser Thomson scattering

2021 ◽  
Vol 92 (7) ◽  
pp. 073001
Author(s):  
O. McCormack ◽  
L. Giudicotti ◽  
A. Fassina ◽  
R. Pasqualotto
Keyword(s):  
Thomson Scattering ◽  
Beam Path ◽  
Dual Laser

Measurement of non-Maxwellian electron velocity distributions in a reflex discharge

1978 ◽  
Vol 19 (2) ◽  
pp. 267-280 ◽  
Author(s):  
C. R. Phipps ◽  
D. Bershader
Keyword(s):  
Magnetic Field ◽  
Langmuir Probe ◽  
Thomson Scattering ◽  
Laser Wavelength ◽  
Stray Light ◽  
Electron Velocity ◽  
Magnetic Field Direction ◽  
Electron Velocity Distribution ◽  
Time Resolved ◽  
Reflex Discharge

Thomson scattering was used to determine space- and time-resolved electron velocity distribution components parallel and transverse to the magnetic field direction in a Penning-type reflex discharge in hydrogen. Electron densities were of the order 1013 cm-3, and temperatures about 3eV. For magnetic field strengths less than about 200 G, Maxwellian distributions were obtained over an energy range six times the thermal energy. Temperatures were in excellent agreement with Langmuir probe data. However, for fields of about 4500 G chaotic plasma potentials were observed with the Langmuir probe. In this regime, in which the plasma was unstable, Thomson scattering showed electron velocity distributions having central temperatures of about 2eV and wing temperatures of 15–20 eV. The experiment design employed led to extremely low stray light levels permitting clean measurements at the laser wavelength and detection of scattered signals as faint as two photons.

Ultraviolet Absorption of Refractory Elements by a Dual Laser Plasma Method

1988 ◽  
Vol 102 ◽  
pp. 243-246
Author(s):  
J.T. Costello ◽  
W.G. Lynam ◽  
P.K. Carroll
Keyword(s):  
Absorption Spectra ◽  
Laser Plasma ◽  
Optical Pulse ◽  
Ionic Species ◽  
Neutral Species ◽  
Plasma Method ◽  
Plasma Technique ◽  
Refractory Elements ◽  
Delay Times ◽  
Dual Laser

AbstractThe dual laser-produced plasma technique for the study of ionic absorption spectra has been developed by the use of two Q-switched ruby lasers to enable independent generation of the absorbing and back-lighting plasmas. Optical pulse handling is used in the coupling cicuits to enable reproducible pulse delays from 250 nsec. to 10 msec, to be achieved. At delay times > 700 nsec. spectra of essentially pure neutral species are observed. The technique is valuable, not only for obtaining the neutral spectra of highly refractory and/or corrosive materials but also for studying behaviour of ionic species as a function of time. Typical spectra are shown in Fig. 1.

Imaging nanostructures on ablated kapton polymide

1993 ◽  
Vol 51 ◽  
pp. 872-873
Author(s):  
Daniel L. Callahan ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Polymer Surface ◽  
Grating Period ◽  
Laser Wavelength ◽  
Integrated Devices ◽  
Transmission Electron ◽  
Excimer Laser Irradiation ◽  
Produce Line ◽  
Line Patterns ◽  
Anisotropic Conduction

Excimer laser irradiation has been used to interferometrically ablate submicron line patterns on to Kapton polyimide. Such patterned material may exhibit highly anisotropic conduction as was predicted from previous studies showing enhanced conductivity from uniformly ablated material. We are currently exploiting this phenomenon to create integrated devices using conventional polymers as both dielectrics and conductors. Extensive scanning electron microscopy (SEM) and limited transmission electron microscopy (TEM) have been conducted in order to characterize the morphology of such patterned nanostructures as a function of processing conditions.The ablation technique employed produces an interference pattern on the polymer surface of period equal to half that of a diffraction grating period, independent of the laser wavelength. In these experiments, a 328 nm grating has been used to produce line patterns of 164 nm line-spacings as shown in Figures 1 and 2. A 200 Å Au coating has been used to both prevent charging and, perhaps more importantly, enhance contrast.

THOMSON SCATTERING WITH A HIGH BACKGROUND LEVEL OF PLASMA RADIATION

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-851-C7-852
Author(s):  
B. Van der Sijde ◽  
T. Poorter ◽  
S. Adema ◽  
B. F.M. Pots ◽  
D. C. Schram
Keyword(s):  
Background Level ◽  
Thomson Scattering ◽  
Plasma Radiation ◽  
High Background

Linear and Nonlinear Optical Properties of Natural Dyes Freestanding Films and Application in Optical Limiting

2020 ◽  
pp. 139-143
Keyword(s):  
Absorption Coefficient ◽  
Water Solution ◽  
Optical Limiting ◽  
Refraction Index ◽  
Laser Wavelength ◽  
Solid State Laser ◽  
Natural Dyes ◽  
Linear And Nonlinear ◽  
532 Nm ◽  
Absorbance Spectra

Natural dyes were followed and prepared from a pomegranate, purple carrot, and eggplant peel. The absorbance spectra was measured in the wavelength range 300-800 nm. The linear properties measurements of the prepared natural dye freestanding films were determined include absorption coefficient (α0), extinction coefficient (κ), and linear refraction index (n). The nonlinear refractive index n2 and nonlinear absorption coefficient β2 of the natural dyes in the water solution were measured by the optical z-scan technique under a pumped solid state laser at a laser wavelength of 532 nm. The results indicated that the pomegranate dye can be promising candidates for optical limiting applications with significantly low optical limiting of 3.5 mW.

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