Research of the Reactivity Photoacoustic Characteristics of PETN and HNS Induced by Laser

2013 ◽  
Vol 423-426 ◽  
pp. 479-482
Author(s):  
Hui E Wang ◽  
Wei Zhang ◽  
Rui Qi Shen ◽  
Ying Hua Ye ◽  
Li Zhi Wu
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Analysis ◽  
Optical Absorption ◽  
Laser Energy ◽  
Photoacoustic Signal ◽  
Optical Absorption Coefficient ◽  
Ignition Energy ◽  
Doping Amount ◽  
Incident Laser ◽  
Incident Laser Energy

The reactivity photoacoustic technology was used to detect the laser induced photoacoustic spectroscopy characteristics of explosives (PETN and HNS). The results showed that: the reflectivity of pure PETN and HNS under laser irradiation was large and the photoacoustic signal was weak. After doping with carbon nanotubes (CNTs) and carbon black (CB), the reflectivity decreased. The photothermal conversion and the optical absorption coefficient rate increased and the photoacoustic signal enhanced. For the same sample, the intensity of the signal was proportional to the incident laser energy. For the same explosives and under the same doping amount, the photoacoustic signal of the CNTs doped sample is greater than that of the CB doped sample. For the same sample and the same dopant, the greater the amount of doping, the stronger the photoacoustic signal. There was optimum ignition energy. By using TG-DSC technology for thermal analysis of the samples, the results from the thermal analysis could explain the reactivity photoacoustic experiment.

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.

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 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.

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.

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.

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.

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