Early-stage plasma dynamics with air ionization during ultrashort laser ablation of metal

2011 ◽  
Vol 18 (9) ◽  
pp. 093302 ◽  
Author(s):  
Wenqian Hu ◽  
Yung C. Shin ◽  
Galen King
Keyword(s):  
Laser Ablation ◽  
Early Stage ◽  
Plasma Dynamics ◽  
Air Ionization ◽  
Ultrashort Laser

Early-Stage Evolution of Electrons Emitted From Metal Target Surface During Ultrashort Laser Ablation in Vacuum

2011 ◽  
Author(s):  
Sha Tao ◽  
Benxin Wu
Keyword(s):  
Heat Transfer ◽  
Laser Ablation ◽  
Electric Field ◽  
Early Stage ◽  
Research Work ◽  
Target Surface ◽  
Electron Mass ◽  
Metal Target ◽  
Free Electron Density ◽  
Ultrashort Laser

The early-stage evolution of electrons emitted from a metal target surface during ultrashort laser ablation in vacuum has been studied using a physics-based model. This kind of research work has been rarely reported in literature. In the model, the target heat transfer process is simulated by solving the two-temperature heat transfer equations, based on which the photoemission and thermionic emission of electrons from the target surface are calculated. The early-stage evolution of emitted electrons is described by solving the electron mass, momentum, and energy conservation equations, coupled with the Poisson’s equation that governs the developed electric field. The study shows that a relatively very high free electron density can be developed near the target surface, and the front of emitted electrons propagates very fast into the vacuum. The developed electric field strongly affects the evolution of emitted electrons. Using the physics-based model, the temporal variation and the spatial distribution of the emitted electron number density, and velocity will be studied and discussed. The early-stage evolution of the emitted electrons may affect the possible subsequent hydrodynamic motion in the target, and the resulted plasma formation and material removal (laser ablation) processes. Therefore, this study provides very useful information for the understanding of ultrashort laser-material interaction, laser-induced plasma, laser ablation (machining), and other relevant processes.

Ultrashort laser ablation of bulk copper targets: Dynamics and size distribution of the generated nanoparticles

2014 ◽  
Vol 115 (24) ◽  
pp. 243301 ◽  
Author(s):  
N. Tsakiris ◽  
K. K. Anoop ◽  
G. Ausanio ◽  
M. Gill-Comeau ◽  
R. Bruzzese ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Size Distribution ◽  
Ultrashort Laser

scholarly journals Formation of nanostructures at laser ablation under the action of ultrashort laser impulses on a surface of solid states

2010 ◽  
Vol 5 ◽  
pp. 213-219 ◽  
Author(s):  
M.N. Gerke ◽  
K.S. Khorkov ◽  
O.B. Telushko ◽  
O.N. Bolshakova ◽  
V.G. Prokoshev ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Solid States ◽  
Ultrashort Laser

scholarly journals Phase 2 Open-Label Trial Investigating Percutaneous Laser Ablation for Treatment of Early-Stage Breast Cancer: MRI, Pathology, and Outcome Correlations

2018 ◽  
Vol 25 (10) ◽  
pp. 2958-2964 ◽  
Author(s):  
Barbara Schwartzberg ◽  
John Lewin ◽  
Osama Abdelatif ◽  
Jacqueline Bernard ◽  
Hanadi Bu-Ali ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Ductal Carcinoma ◽  
Early Stage ◽  
False Negative ◽  
Mri Imaging ◽  
Open Label ◽  
Invasive Ductal Breast Carcinoma ◽  
Intention To Treat ◽  
Ki67 Staining ◽  
Percutaneous Laser Ablation

Abstract Background An institutional review board-approved, multicenter clinical trial was designed to determine the efficacy and outcome of percutaneous laser ablation (PLA) in the treatment of invasive ductal breast carcinoma (IDC). Post-ablation magnetic resonance imaging (MRI) was compared with surgical pathology in evaluation of residual post-ablation IDC and ductal carcinoma in situ. Methods Patients with a single focus of IDC 20 mm or smaller by pre-ablation MRI were treated with PLA. The patients underwent a 28-day post-ablation MRI, followed by surgical resection. Cell viability criteria were applied to pre- and post-ablation pathology specimens, which evaluated hematoxylin–eosin (H&E), cytokeratin (CK) 8/18, estrogen receptor, and Ki67 staining patterns. Results In this study, 61 patients were reported as the intention-to-treat cohort for determination of PLA efficacy. Of these 61 patients, 51 (84%) had complete tumor ablation confirmed by pathology analysis. One subject’s MRI imaging was not performed per protocol, which left 60 subjects evaluable for MRI pathology correlation. Five patients (8.3%) had residual IDC shown by both MRI and pathology. Post-ablation discordance was noted between MRI and pathology, with four patients (6.7%) false-positive and four patients (6.7%) false-negative. The negative predictive value (NPV) of MRI for all the patients was 92.2% (95% confidence interval [CI], 71.9–91.9%). Of the 47 patients (97.9%) with tumors 15 mm or smaller, 46 were completely ablated, with an MRI NPV of 97.7% (95% CI, 86.2–99.9%). Conclusions Percutaneous laser ablation is a potential alternative to surgery for treatment of early-stage IDC. Strong correlations exist between post-ablation MRI and pathologic alterations in CK8/18, ER, and Ki67 staining.

Sign in / Sign up

Export Citation Format

Share Document