Pulsed laser ablation plasmas generated in CO2 under high-pressure conditions up to supercritical fluid

2012 ◽  
Vol 101 (22) ◽  
pp. 224103 ◽  
Author(s):  
Toru Kato ◽  
Sven Stauss ◽  
Satoshi Kato ◽  
Keiichiro Urabe ◽  
Motoyoshi Baba ◽  
...  
Keyword(s):  
High Pressure ◽  
Laser Ablation ◽  
Supercritical Fluid ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation

Dynamics of pulsed laser ablation in high-density carbon dioxide including supercritical fluid state

2013 ◽  
Vol 114 (14) ◽  
pp. 143303 ◽  
Author(s):  
Keiichiro Urabe ◽  
Toru Kato ◽  
Sven Stauss ◽  
Shohei Himeno ◽  
Satoshi Kato ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Laser Ablation ◽  
Supercritical Fluid ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
High Density ◽  
Fluid State ◽  
Supercritical Fluid State

Size Effect on the Transformation from Graphite to Nanodiamonds

2014 ◽  
Vol 787 ◽  
pp. 412-418 ◽  
Author(s):  
Fei Tian ◽  
Hong Yang ◽  
Yong Guang Zhao ◽  
Hong Mei Cao
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Laser Ablation ◽  
Metastable Phase ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Vapor Condensation ◽  
Research Field ◽  
Laser Vaporization ◽  
Laser Ablation In Liquid

The synthesis of nanodiamonds by pulsed-laser ablation in liquid (PLAL) is an attractive research field in developing well-dispersed fluorescent nanodiamonds for bioimaging and life science. However, nanodiamonds are quite different from their widely pursued carbon allotropes both in synthesis conditions and physical properties. It is a great challenge to synthesize metastable phase nanodiamonds that prefer high temperature and high pressure. Despite the progress in the synthesis of nanodiamond by pulsed-laser ablation of graphite target using different laser power densities under room conditions, the transformation from graphite to nanodiamonds are not yet well explained. In order to have a better understanding to the formation of metastable nanodiamonds upon PLAL, the formation of nanodiamond has been elucidated from both the aspects of thermodynamics and kinetics. Due to low laser intensity and long wavelength, synthesis of nanodiamonds is the result of high cooling velocity of high-pressure and high-temperature carbon vapor condensation formed under laser vaporization of graphite particles. When diamond nuclei grow into the right size, they cannot increase and the graphite nucleation begins to form and grow on the diamond at given conditions due to long pulse width for ms-pulsed laser. In fact, the diamond particles enwrapped several layers of graphite have obtained. Moreover, the reasons related 3~6nm diamonds prepared by this new process and having narrow size distribution are also discussed.

Study of Unsteady Supersonic Jet Using Shock Tube with Small High-Pressure Chamber with Elliptical Cell

2013 ◽  
Vol 767 ◽  
pp. 80-85 ◽  
Author(s):  
Motoki Sakamoto ◽  
Masazumi Matsui ◽  
Hiroshi Fukuoka ◽  
Minoru Yaga ◽  
Toshio Takiya
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Laser Ablation ◽  
Shock Tube ◽  
Static Pressure ◽  
Focal Point ◽  
Supersonic Jet ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
High Pressure Chamber

The unsteady supersonic jet formed by the shock tube with small high-pressure chamber was used as a simple alternative model of Pulsed laser ablation. Since the pressure of the shock wave formed by Pulsed laser ablation is very high, the interaction between the shock wave and the plume is important for the formation of nanoparticles especially under high background gas pressure. An elliptical cell is used for controlling the shock wave. The shock wave discharged in one focal point converge another focal point. Numerical calculation was carried out by solving the axisymmetric two-dimensional compressible Navier-Stokes equations. The wall static pressure monitored at the center of substrate is used to evaluate the influence of the shape and the pressure ratio on the behavior of the shock wave, the plume, and their interaction. As a result, it was found that the vortex ring was generated downstream of the cell, which is followed by the discharging shock wave from the cell exit. It was also found that the influence of the vortex ring on the wall static pressure at the center of the substrate.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

scholarly journals Doping nanoparticles using pulsed laser ablation in a liquid containing the doping agent

2019 ◽  
Vol 1 (10) ◽  
pp. 3963-3972 ◽  
Author(s):  
Arsène Chemin ◽  
Julien Lam ◽  
Gaétan Laurens ◽  
Florian Trichard ◽  
Vincent Motto-Ros ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Doping Agent ◽  
Laser Ablation In Liquids ◽  
Dope Nanoparticles

While doping is crucial for numerous technological applications, its control remains difficult especially when the material is reduced down to the nanometric scale. We suggest a new way to dope nanoparticles using laser ablation in liquids.

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