Angular Distribution and Ion Time of Flight Produced on Silicon Target by Laser Irradiation

2011 ◽  
Vol 227 ◽  
pp. 31-34
Author(s):  
Yasmina Belaroussi ◽  
Tahar Kerdja ◽  
Smail Malek
Keyword(s):  
Angular Distribution ◽  
Laser Energy ◽  
Angular Distributions ◽  
Physical Processes ◽  
Incident Laser ◽  
Ion Energy ◽  
Incident Laser Energy ◽  
Silicon Target ◽  
The Mean

The growth of thin films by laser ablation involves very complex physical processes. The quality of the layer and stoechiometry of the deposits depend on key parameters like the ion energy and their angular distribution. The evolution of ions number and energy, and the angular distributions in regards to the incident laser energy, have been studied by the mean of a charges collector. We present the polar diagrams of energy and number of ions collected by irradiating a silicon target using an excimer laser at different energies.

Laser Assisted E-Beam Epitaxial Growth of Si/Ge Alloys on Si

1990 ◽  
Vol 202 ◽  
Author(s):  
Paul Martin Smith ◽  
S. Lombardo ◽  
M.J. Uttormark ◽  
Stephen J. Cook ◽  
Michael O. Thompson
Keyword(s):  
Film Thickness ◽  
Epitaxial Growth ◽  
Room Temperature ◽  
Laser Energy ◽  
Incident Laser ◽  
Fine Grained ◽  
Surface Mobility ◽  
Incident Laser Energy ◽  
Enhanced Surface ◽  
Xecl Excimer Laser

ABSTRACTA novel laser-assisted technique for e-beam epitaxial growth of GexSi1−x alloys on <100> Si has been investigated. During deposition, a XeCl excimer laser is used to either heat, or to melt and crystallize, the GexSi1−x continuously as the material is evaporated. This process of heating or melting and crystallizing can be continued until the desired film thickness is achieved. At incident laser energy densities which produce melt, the underlying crystalline seed ensures epitaxial growth during the subsequent solidification. Depositions of films up to 3 at.% Ge under this liquid regime, with substrates held nominally at room temperature, exhibited complete epitaxial growth. At energy densities below the melt threshold, enhanced surface mobility for epitaxial alignment is required. Depositions in this regime exhibit only partial epitaxial growth with conversion to fine grained polycrystalline growth after short distances.

The effect of incident laser energy on pulsed laser deposition of HgCdTe films

2009 ◽  
Vol 311 (4) ◽  
pp. 1087-1090 ◽  
Author(s):  
Mei Liu ◽  
Baoyuan Man ◽  
Xingchao Lin ◽  
Xiangyang Li
Keyword(s):  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Incident Laser ◽  
Incident Laser Energy

scholarly journals Angular distributions of ions from laser-produced plasma

1999 ◽  
Vol 17 (2) ◽  
pp. 307-312 ◽  
Author(s):  
E. WORYNA ◽  
P. PARYS ◽  
J. WOŁOWSKI ◽  
J. KRÁSA ◽  
L. LÁSKA ◽  
...  
Keyword(s):  
Group Velocity ◽  
Laser Energy ◽  
Laser System ◽  
Angular Distributions ◽  
Energy Analyzer ◽  
Ion Energy ◽  
Preferred Direction ◽  
Maximum Charge ◽  
Ion Emission ◽  
Fast Ion

This paper presents comprehensive experimental results of angular distributions of ions emitted from laser-produced plasmas. Performing a series of laser shots onto planar Sn, Au, and Pb targets, both the focusing conditions as well as the tilt angle of the target were changed to study the effect on the plasma expansion. In the experiments, the iodine laser system PERUN (laser energy of 30 J in 350 ps of duration) with laser power density of 5 × 1014 W/cm2 was used. For plasma diagnostics four ion collectors and an ion-energy analyzer were applied. Comparison of angular distribution of the fast ion group (velocity within the range of 1–3.4 × 108 cm/s) and of the slow ion group (velocity within the range of 0.14–1 × 108 cm/s) shows distinct differences. The preferred direction of ion emission of these groups depends seriously on focusing conditions. When setting the focus on the in-focus position both groups of ions are peaked in the direction close to the target normal. The maximum charge of ions registered by the ion-energy analyzer were 36+, 51+, and 49+ for Sn, Au, and Pb, respectively.

Raman Spectroscopy on Individual Identified Carbon Nanotubes

2012 ◽  
Vol 1407 ◽  
Author(s):  
R. Parret ◽  
D. Levshov ◽  
T. X. Than ◽  
D. Nakabayashi ◽  
T. Michel ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Laser Energy ◽  
Low Frequency ◽  
Radial Breathing Mode ◽  
Incident Laser ◽  
Mechanical Coupling ◽  
Incident Laser Energy ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

ABSTRACTIn this paper, we discuss the low-frequency range of the Raman spectrum of individual suspended index-identified single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs). In SWCNTs, the role of environment on the radial breathing mode (RBM) frequency is discussed. We show that the interaction between the surrounding air and the nanotube does not induce a RBM upshift. In several DWCNTs, we evidence that the low-frequency modes cannot be connected to the RBM of each related layer. We discuss this result in terms of mechanical coupling between the layers which results in collective radial breathing-like modes. The mechanical coupling qualitatively explains the observation of Raman lines of radial breathing-like modes, whenever only one of the layers is in resonance with the incident laser energy.

Understanding the contribution of energy and angular distribution in the morphology of thin films using Monte Carlo simulation

2018 ◽  
Vol 24 (3) ◽  
pp. 215-224
Author(s):  
Abdelkader Bouazza ◽  
Abderrahmane Settaouti
Keyword(s):  
Thin Films ◽  
Monte Carlo ◽  
Angular Distribution ◽  
Great Influence ◽  
Angular Distributions ◽  
High Agreement ◽  
Sputtering Yield ◽  
Two Parameters ◽  
Very High

Abstract The energy and the angular distribution of atoms are considered like two parameters most influent in the optimization of the sputtering and subsequently on the deposit, resulting in films having the desired properties (homogeneity in thickness, composition identical to that of the evaporated material). Moreover, a great influence on the shape and quality of thin films is obtained. In this work, a simulation with a Monte Carlo (MC) method is used to calculate the sputtering yield for different energies and angular distributions of atoms of metals (Cu, Al and Ag) and semiconductors (Ge, Si and Te) bombarded by different gas particles (Ar, Xe and Ne). Our results showed that when arriving at a certain energy value E_{\rm max} , sputtering yield will be in maximum Y1_{\rm max} . Applying this E_{\rm max} and with variation in the angular distribution, we will obtain \theta_{\rm max} corresponding to the maximum of sputtering yield Y2_{\rm max} . These two values ( E_{\rm max} , \theta_{\rm max} ) give the maximum of atoms sputtered and as a result, the films will be uniform. The obtained results are in very high agreement with other works, which validates our calculations.

scholarly journals Numerical modeling of quantum beam generation from ultra-intense laser-matter interactions

2015 ◽  
Vol 33 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Tatsufumi Nakamura ◽  
Takehito Hayakawa
Keyword(s):  
Energy Transport ◽  
Laser Energy ◽  
Radiation Reaction ◽  
High Energy ◽  
Intense Laser ◽  
Incident Laser ◽  
Particle In Cell ◽  
Transport Code ◽  
Incident Laser Energy ◽  
Good Agreement

AbstractWhen intense laser beams interact with solid targets, high-energy photons are effectively generated via radiation reaction effect. These photons receive a large portion of the incident laser energy, and the energy transport by photons through the target is crucial for the understanding of the laser–matter interactions. In order to understand the energy transport, we newly developed a Particle-in-Cell code which includes the photon–matter interactions by introducing photon macro-particles. Test simulations are performed and compared with simulations using a particle transport code, which shows a good agreement.

Shadowgraph of Pulse CO2 Laser Induced Breakdown in Different Pressure Air

2014 ◽  
Vol 887-888 ◽  
pp. 1001-1004 ◽  
Author(s):  
Yu Zhang ◽  
Duan Yong Li ◽  
Tao Wu
Keyword(s):  
Shock Wave ◽  
Delay Time ◽  
High Speed ◽  
Laser Energy ◽  
Early Stage ◽  
Propagation Speed ◽  
Air Pressure ◽  
Incident Laser ◽  
Incident Laser Energy ◽  
Laser Induced Breakdown

The expansion property of an infrared CO2 laser produced air plasma is characterized using a high-speed imaging shadowgraph technique. The shadowgraphs were taken by a time-gated intensified charge-coupled device at various delay times after single pulses induced gas breakdown. We examined five incident laser energy of 180, 240, 345, 420 and 600 mJ induced air breakdown at the pressure of atmospheric and 104 Pa. A shock wave produced by laser induced breakdown was also observed and its speed was measured as a function delay time between the breakdown and the shadow imaging under different air pressure. The experimental results indicated that the radial and axial shock wave front evolutions showed similar behavior, which increased fast with delay time at early stage and slowly at later stage. The propagation speed of the wavefront was about 2 cm/μs at the initial stage of breakdown, and then decreased very quickly. The propagation speed under low air pressure was higher than that of gases under high pressure and the spark sustained less time at lower pressure. The size of laser induced air spark increased with incident laser energy but not simple linear relationships.

Partitioning the influence of physical processes on the estimation of ichthyoplankton mortality rates. I. Theory

1998 ◽  
Vol 55 (10) ◽  
pp. 2189-2205 ◽  
Author(s):  
J A Helbig ◽  
P Pepin
Keyword(s):  
Temporal Variability ◽  
Mortality Rates ◽  
Field Sampling ◽  
Physical Processes ◽  
Length Scales ◽  
Sampling Plans ◽  
The Mean ◽  
Mean Current ◽  
Mortality Estimates

This paper examines the effects of natural spatial-temporal variability in ichthyoplankton concentration and in currents on the estimation of mortality rates. We derive expressions for the biases and variances of mortality estimates computed from the change in plankton concentration between successive surveys as well as estimates of the corrections due to the advection of plankton. We demonstrate that estimate bias depends primarily on how well the mean current and mean ichthyoplankton fields are sampled whereas the variance depends on the variability about the mean in currents and plankton concentration and on the time and length scales on which this variability occurs. Simplified versions of the theoretical expressions provide an easily implemented framework for evaluating the quality of field sampling plans.

scholarly journals X-ray emission from laser-irradiated gold targets with surface modulation

2001 ◽  
Vol 19 (2) ◽  
pp. 241-247 ◽  
Author(s):  
T. DESAI ◽  
H. DAIDO ◽  
M. SUZUKI ◽  
N. SAKAYA ◽  
A.R. GUERREIRO ◽  
...  
Keyword(s):  
Laser Energy ◽  
Emission Spectra ◽  
Plasma Confinement ◽  
Incident Laser ◽  
Experimental Conditions ◽  
Groove Surface ◽  
X Ray ◽  
Incident Laser Energy ◽  
Surface Modulation ◽  
Planar Target

X-ray emission spectra in the 5–22 nm range were recorded from planar and structured (meshlike groove surface) gold targets at 45° and 90° to the laser axis. A laser beam of 10-ns duration with EL ≤ 700 mJ and 1.06-μm wavelength was used for the experiment. Experimental results indicate an enhanced X-ray yield from a structured target as compared to a planar target under identical experimental conditions. Increased X-ray emission is attributed to plasma confinement and the possibility of conversion of kinetic energy into localized thermal energy of the plasma. Results are analyzed explicitly on the incident laser energy.

scholarly journals Conversion of laser light into soft X rays with 3-ns and 30-ps laser pulses

1991 ◽  
Vol 9 (2) ◽  
pp. 551-562 ◽  
Author(s):  
K. Eidmann ◽  
W. Schwanda
Keyword(s):  
Laser Light ◽  
Laser Energy ◽  
Short Pulse ◽  
Laser Pulses ◽  
X Rays ◽  
Incident Laser ◽  
X Ray ◽  
Transmission Grating ◽  
Incident Laser Energy ◽  
Temporal And Spatial

The X-ray emission from planar targets made of aluminum, copper, or gold irradiated by a frequency-doubled Nd laser (530-nm wavelength and 1012–1014-W/cm2 laser intensity) was measured at two pulse durations: 3 ns and 30 ps. We absolutely measured the X-ray emission with spectral, temporal, and spatial resolution in the wavelength range 3 Å < λ < 250 Å by using filtered bolometers, a transmission grating spectrometer, X-ray diodes, and an X-ray streak camera as diagnostics. In addition, the absorption of laser light was measured. For the short, 30-ps laser pulse the conversion of incident laser energy into X rays was considerably less than that with the long, 3-ns pulse. This is caused by less absorption of laser light and, in addition, by less conversion of absorbed laser energy into X rays in the case of the short pulse. The results are compared with numerical simulations performed with the MULTI hydrocode.

Sign in / Sign up

Export Citation Format

Share Document