Development of a Nomarski-type multi-frame interferometer as a time and space resolving diagnostics for the free electron density of laser-generated plasma

2012 ◽  
Vol 83 (4) ◽  
pp. 043501 ◽  
Author(s):  
M. Börner ◽  
J. Fils ◽  
A. Frank ◽  
A. Blažević ◽  
T. Hessling ◽  
...  
Keyword(s):  
Electron Density ◽  
Free Electron ◽  
Time And Space ◽  
Free Electron Density

Transition from a Bloch-Wilson to a free-electron density of states in Znn− clusters

2005 ◽  
Vol 123 (22) ◽  
pp. 221102 ◽  
Author(s):  
Oleg Kostko ◽  
Gert Wrigge ◽  
Ori Cheshnovsky ◽  
Bernd v. Issendorff
Keyword(s):  
Electron Density ◽  
Density Of States ◽  
Free Electron ◽  
Free Electron Density ◽  
Electron Density Of States

Evidence for non-equilibrium free electron density in AlGaAs at low temperatures

1991 ◽  
Vol 78 (2) ◽  
pp. 159-162 ◽  
Author(s):  
C. Ghezzi ◽  
R. Mosca ◽  
A. Bosacchi ◽  
S. Franchi ◽  
E. Gombia ◽  
...  
Keyword(s):  
Electron Density ◽  
Free Electron ◽  
Low Temperatures ◽  
Free Electron Density ◽  
Non Equilibrium

Analysis of USP Laser Induced Ablation Threshold in Transparent Aqueous Tissue

2012 ◽  
Author(s):  
Jian Jiao ◽  
Zhixiong Guo
Keyword(s):  
Electron Density ◽  
Free Electron ◽  
Present Model ◽  
Ablation Threshold ◽  
Ablation Process ◽  
Free Electrons ◽  
Free Electron Density ◽  
Avalanche Ionization ◽  
Transparent Media ◽  
First Time

The ultrashort pulsed (USP) laser induced plasma-mediated ablation in transparent media is modeled and studied in this work. We propose that a certain number of free electrons are required to trigger the avalanche ionization for the first time. Based on this assumption, the ablation process is postulated as two separate processes — the multiphoton and avalanche ionizations. For USP laser induced ablation in the transparent corneal epithelium at 800 nm, the critical seed free-electron density and the time to initialize the avalanche ionization for pulse widths from picoseconds down to the femtoseconds range are calculated. It is found that the critical seed free-electron density decreases as the pulse width increases, obeying a tp−5.65 rule. Moreover, this model is also extended to the estimation of crater sizes in USP laser ablation of polydimethylsiloxane (PDMS). The crater sizes ablated in a PDMS by a 900 fs pulsed laser at wavelength 1552 nm are modeled using the present model, and the results match with the existing experimental measurements.

Materials Removals During Femtosecond Laser Non-Thermal Ablation of Dielectrics

2006 ◽  
Author(s):  
Lan Jiang ◽  
Hai-Lung Tsai
Keyword(s):  
Experimental Data ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Electron Density ◽  
Free Electron ◽  
Femtosecond Laser Ablation ◽  
Threshold Fluence ◽  
Plasma Model ◽  
Free Electron Density ◽  
Two Temperature

It remains a big challenge to theoretically predict the material removals mechanism in femtosecond laser ablation. To bypass this unresolved problem, many calculations of femtosecond laser ablation of non-metals have been based on free electron density distribution without the actual consideration of the phase change mechanism. However, this widely-used key assumption needs further theoretical and experimental confirmations. By combining the plasma model and improved two-temperature model developed by the authors, this study focuses on investigating ablation threshold fluence, depth, and shape during femtosecond laser ablation of dielectrics through non-thermal processes (the Coulomb explosion and electrostatic ablation). The predicted ablation depths and shapes in fused silica, by using 1) the plasma model only and 2) the plasma model plus the two-temperature equation, are both in agreement with published experimental data. The widely-used assumptions for threshold fluence, ablation depth, and shape in the plasma model based on free electron density are validated by the comparison study and experimental data.

Free electron density and mobility in high-quality 4H–SiC

2000 ◽  
Vol 77 (26) ◽  
pp. 4359-4361 ◽  
Author(s):  
J. Pernot ◽  
S. Contreras ◽  
J. Camassel ◽  
J. L. Robert ◽  
W. Zawadzki ◽  
...  
Keyword(s):  
Electron Density ◽  
Free Electron ◽  
High Quality ◽  
Free Electron Density
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