A low-wavenumber-extended confocal Raman microscope with very high laser excitation line discrimination

2011 ◽  
Vol 82 (1) ◽  
pp. 013705 ◽  
Author(s):  
Sergei Lebedkin ◽  
Carolin Blum ◽  
Ninette Stürzl ◽  
Frank Hennrich ◽  
Manfred M. Kappes
Keyword(s):  
Laser Excitation ◽  
High Laser ◽  
Excitation Line ◽  
Confocal Raman ◽  
Very High

Observations on the Growth of YBa2Cu3O7 Thin Films at Very High Laser Fluences

1995 ◽  
Vol 388 ◽  
Author(s):  
Rand R. Biggers. ◽  
M. Grant Norton ◽  
I. Maartense ◽  
T.L. Peterson ◽  
E. K. Moser ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
High Fluences ◽  
Laser Fluences ◽  
High Laser ◽  
High Laser Fluences ◽  
Very High

AbstractThe pulsed-laser deposition (PLD) technique utilizes one of the most energetic beams available to form thin films of the superconducting oxide YBa2Cu3O7 (YBCO). IN this study we examine the growth of YBCO at very high laser fluences (25 to 40 J/cm2); a more typical fluence for PLD would be nearer to 3 J/cm2. the use of high fluences leads to unique film microstructures which, in some cases, appear to be related to the correspondingly higher moveabilities of the adatoms. Films grown on vicinal substrates, using high laser fluences, exhibited well-defined elongated granular morphologies (with excellent transition temperature, Tc, and critical current density, Jc). Films grown on vicinal substrates using off-axis magnetron sputtering, plasma-enhanced metal organic chemical vapor deposition (PE-MOCVD), or PLD at more typical laser fluences showed some similar morphologies, but less well-defined. Under certain growth conditions, using high laser fluences with (001) oriented substrates, the YBCO films can exhibit a mixture of a- and c-axis growth where both crystallographic orientations nucleate on the substrate surface at the same time, and grow in concert. the ratio of a-axis oriented to c-axis oriented grains is strongly affected by the pulse repetition rate of the laser.

Resonant Photoluminescence Excitation in GaAs Grown Directly on Si

1988 ◽  
Vol 116 ◽  
Author(s):  
S. Zemon ◽  
C. Jagannath ◽  
S. K. Shastry ◽  
W. J. Miniscalco ◽  
G. Lambert
Keyword(s):  
Ground State ◽  
Heavy Hole ◽  
Laser Excitation ◽  
Free Exciton ◽  
Light Hole ◽  
The Other ◽  
Organometallic Vapor Phase Epitaxy ◽  
Photoluminescence Excitation ◽  
Excitation Spectra ◽  
Excitation Line

AbstractWe describe new results observed during resonant excitation in the excitonic region of GaAs grown directly on Si by organometallic vapor phase epitaxy. Two resolved features were found in the light hole photoluminescence (PL) region, one identified with a free exciton process and the other with donor-related transitions. Features which track the laser excitation line were observed and identified with a process in which a donor is excited from the n=l ground state to an n=2 excited state. The PL excitation spectra associated with these features have spectral widths as narrow as 1.5 meV. PL spectral widths of ~3 meV have been attained for the heavy hole exciton band, representing the narrowest value obtained for OMVPE material and an improvement of about 30% over our best previous results.

cw CO2 laser-induced and SF6-sensitized decomposition of methyl iodide-d3

1983 ◽  
Vol 48 (11) ◽  
pp. 3261-3269 ◽  
Author(s):  
Jaroslav Rejnek ◽  
Marie Jakoubková ◽  
Pavel Engst ◽  
Milan Horák
Keyword(s):  
Decomposition Rate ◽  
Total Pressure ◽  
Laser Excitation ◽  
Irradiation Time ◽  
Product Distribution ◽  
Recombination Reaction ◽  
Reaction Step ◽  
Abstraction Reaction ◽  
Excitation Line ◽  
Cw Co2 Laser

The decomposition of CD3I initiated by the irradiation of a cw CO2 laser was studied in the presence of the SF6 sensitizer. The first reaction step of the decomposition produces CD3 radical that yields either methane-d4 (the abstraction reaction of „hot" radicals), or ethane-d6 (the recombination reaction of „cold" radicals). The effect of the total pressure and the composition of the reaction mixture, that of the laser excitation line and output and that of the irradiation time upon the decomposition rate and the product distribution was examined.

Note: Deep ultraviolet Raman spectrograph with the laser excitation line down to 177.3 nm and its application

2014 ◽  
Vol 85 (4) ◽  
pp. 046105 ◽  
Author(s):  
Shaoqing Jin ◽  
Fengtao Fan ◽  
Meiling Guo ◽  
Ying Zhang ◽  
Zhaochi Feng ◽  
...  
Keyword(s):  
Laser Excitation ◽  
Excitation Line ◽  
Deep Ultraviolet

Relativistic and ponderomotive self-focusing at laser–plasma interaction

1999 ◽  
Vol 61 (2) ◽  
pp. 263-273 ◽  
Author(s):  
FREDERICK OSMAN ◽  
REYNALDO CASTILLO ◽  
HEINRICH HORA
Keyword(s):  
Refractive Index ◽  
Laser Plasma ◽  
Laser Intensity ◽  
Relativistic Effects ◽  
Electron Motion ◽  
Nonlinear Plasma ◽  
Laser Plasma Interaction ◽  
Self Focusing ◽  
High Laser ◽  
Very High

The nonlinear plasma dielectric function due to relativistic electron motion is derived. From this, one can obtain the nonlinear refractive index of the plasma and estimate the importance of relativistic self-focusing in comparison with ponderomotive non-relativistic self-focusing at very high laser intensities. When the laser intensity is very high, ponderomotive self-focusing will be dominant. However, at some point, when the oscillating velocity of the plasma electrons becomes very large, relativistic effects will also play a role in self-focusing.

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