scholarly journals Nuclear Fusion Effects Induced in Intense Laser-Generated Plasmas

10.14311/1775 ◽  
2013 ◽  
Vol 53 (2) ◽  
Author(s):  
Lorenzo Torrisi ◽  
Salvatore Cavallaro ◽  
Mariapompea Cutroneo ◽  
Josef Krasa
Keyword(s):  
Laser Energy ◽  
Incidence Angle ◽  
High Vacuum ◽  
Laser Pulses ◽  
Intense Laser ◽  
Carbon Ions ◽  
Plasma Generation ◽  
High Laser ◽  
High Laser Energy ◽  
Set Up

Deutered polyethylene (CD2)n thin and thick targets were irradiated in high vacuum by infrared laser pulses at 1015W/cm2 intensity. The high laser energy transferred to the polymer generates plasma, expanding in vacuum at supersonic velocity, accelerating hydrogen and carbon ions. Deuterium ions at kinetic energies above 4 MeV have been measured by using ion collectors and SiC detectors in time-of-flight configuration. At these energies the deuterium–deuterium collisions may induce over threshold fusion effects, in agreement with the high D-D cross-section valuesaround 3 MeV energy. At the first instants of the plasma generation, during which high temperature, density and ionacceleration occur, the D-D fusions occur as confirmed by the detection of mono-energetic protonsand neutrons with a kinetic energy of 3.0 MeV and 2.5 MeV, respectively, produced by the nuclear reaction. The number of fusion events depends strongly on the experimental set-up, i.e. on the laser parameters (intensity, wavelength, focal spot dimension), target conditions (thickness, chemical composition, absorption coefficient, presence of secondary targets) and used geometry (incidence angle, laser spot, secondary target positions).A number of D-D fusion events of the order of 106÷7 per laser shot has been measured.

SUPERCONTINUUM SPECTRUM GENERATION IN THE LIQUIDS WITH DIFFERENT BAND GAP THRESHOLDS

2006 ◽  
Vol 15 (04) ◽  
pp. 447-453
Author(s):  
SHIAN ZHANG ◽  
ZHENRONG SUN ◽  
LI DENG ◽  
ZUGENG WANG
Keyword(s):  
Band Gap ◽  
Laser Energy ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Spectral Broadening ◽  
Laser Spectrum ◽  
High Laser ◽  
Supercontinuum Spectrum ◽  
High Laser Energy ◽  
Spectrum Generation

Supercontinuum spectrum generation by femtosecond laser pulses propagating in transparent liquids with different band gap thresholds is investigated. As the laser energy increases, the laser spectrum is strongly broadened and modulated, and finally a supercontinuum spectrum can be observed. The spectral broadening can be mainly attributed to the optical Kerr effect at low laser energy and the plasma created by the multiphoton excitation of electrons from the valence band to the conduction band at high laser energy. It is found that the spectral broadening and modulation strongly depend on the band gap threshold E gap of the medium.

High Performance n- and p-channel Strained Single Grain Silicon TFTs using Excimer Laser

2009 ◽  
Vol 1153 ◽  
Author(s):  
Alessandro Baiano ◽  
Ryoichi Ishihara ◽  
Kees Beenakker
Keyword(s):  
High Performance ◽  
Laser Energy ◽  
Silicon Layer ◽  
Silicon Thin Film ◽  
High Laser ◽  
High Laser Energy ◽  
Single Grain ◽  
Czochralski Process ◽  
Low Temperature Process

AbstractIn this paper we investigate the carriers mobility enhancement of the n- and p-channel single-grain silicon thin-film transistors (SG-TFTs) by μ-Czochralski process at low-temperature process (< 350 °C). The high laser energy density nearby the ablation phenomenon that completely melts the silicon layer during the crystallization is responsible for high tensile strain and good crystal quality of the silicon grains, which lead carriers mobility enhancement.

Effect of Laser Parameter on the Bond Characteristics of Sn-3.5%Ag Solder Ball

2008 ◽  
Vol 580-582 ◽  
pp. 191-196
Author(s):  
Jeng O Kim ◽  
Jae Pil Jung ◽  
Jae Hoon Lee ◽  
Jeong Suh ◽  
Hee Shin Kang
Keyword(s):  
Solder Ball ◽  
Laser Energy ◽  
Focal Point ◽  
Laser Pulses ◽  
Beam Diameter ◽  
Ball Diameter ◽  
Laser Soldering ◽  
Activated Flux ◽  
Set Up ◽  
Bond Characteristics

Pulsed Nd;YAG laser was applied to investigate the bond characteristics of Sn- 3.5wt%Ag (hereafter, Sn-3.5Ag) solder ball. The ball diameter is 500µm, and the UBM (Under Bump Metallurgy) on a FR4-PCB consisted of Cu/Ni/Au from bottom to top with thickness of 50µm/25µm/0.05µm, respectively. A RMA (rosin mildly activated) flux for BGA (Ball Grid Array) was applied before laser soldering to set up the solder ball on the UBM. Laser power was 250W, and its beam diameter at the focal point was around 250µm. Experimental results reveal that the solder ball showed a good bonded state when the laser energy was in the range between 0.8 and 1.0 J. Laser energy lower than 0.8J caused non-wetting of the solder ball, and energy higher than 1.2J showed crack along the UBM. Microstructure of the laser soldered Sn-3.5Ag was examined with the number of pulse, when the frequency, pulse width and laser energy were fixed at 5 Hz, 20 ms and 0.8 J, respectively. The IMC (Intermetallic Compound) of Ag3Sn in the solder changed from acicular to rod type with increasing laser pulses. Ni3Sn4 was produced between the solder and the UBM, and its thickness increased from 0.65 to 1.80µm with increasing number of pulse from 2 to 4. These are thinner than those of general air reflow. Shear strength of the laser soldered ball with output energy of 1 J showed 652.3 gf, and it was similar value compared to the result from hot plate soldering, 654.5 gf.

scholarly journals Development of a 1 TW/35 fs Ti:sapphire Laser Amplifier and Generation of Intense THz Waves Using Two-Color Laser Filamentation

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 316
Author(s):  
Vanessa Ling Jen Phung ◽  
Keekon Kang ◽  
Seongjin Jeon ◽  
Jinju Kim ◽  
Kyungmin Roh ◽  
...  
Keyword(s):  
Laser Energy ◽  
Second Harmonic ◽  
Laser Pulses ◽  
Intense Laser ◽  
Laser Amplifier ◽  
Terahertz Waves ◽  
Regenerative Amplifier ◽  
Central Wavelength ◽  
Particle In Cell ◽  
Ti:Sapphire Laser

We developed a compact Ti:sapphire laser amplifier system in our laboratory, generating intense laser pulses with a peak power of >1 TW (terawatt), a pulse duration of 34 fs (femtosecond), a central wavelength of 800 nm, and a repetition rate of 10 Hz. The laser amplifier system consists of a mode-locked Ti:sapphire oscillator, a regenerative amplifier, and a single-side-pumped 4-pass amplifier. The chirped-pulse amplification (CPA)-based laser amplifier was found to provide an energy of 49.6 mJ after compression by gratings in air, where the pumping fluence of 1.88 J/cm2 was used. The amplified spontaneous emission (ASE) level was measured to be lower than 10−7, and ps-prepulses were in 10−4 or lower level. The developed laser amplifier system was used for the generation of intense THz (terahertz) waves by focusing the original (800 nm) and second harmonic (400 nm) laser pulses in air. The THz pulse energy was shown to be saturated in the high laser energy regime, and this phenomenon was confirmed by fully electromagnetic, relativistic, and self-consistent particle-in-cell (PIC) simulations.

Effect of Laser Energy and Atmosphere on the Emission Characteristics of Laser-Induced Plasmas

1993 ◽  
Vol 47 (10) ◽  
pp. 1659-1664 ◽  
Author(s):  
Mikio Kuzuya ◽  
Hitoshi Matsumoto ◽  
Hideaki Takechi ◽  
Osamu Mikami
Keyword(s):  
Energy Range ◽  
Atmospheric Pressure ◽  
Laser Energy ◽  
Low Energy ◽  
Emission Characteristics ◽  
Yag Laser ◽  
Background Ratio ◽  
High Laser ◽  
High Laser Energy ◽  
Temporal And Spatial

The effects of laser energy and atmosphere on the emission characteristics of laser-induced plasmas were studied with the use of a Q-switched Nd: YAG laser over a laser energy range of 20 to 95 mJ. Argon, helium, and air were used as surrounding atmospheres, and the pressures were changed from atmospheric pressure to 1 Torr. The experimental results showed that the maximum spectral intensity was obtained in argon at around 200 Torr at a high laser energy of 95 mJ, whereas the line-to-background ratio was maximized in helium at around 40 Torr at a low energy of 20 mJ. The results are discussed briefly on the basis of the temporal and spatial observations of the laser-induced plasmas.

scholarly journals Influence of laser incidence angle on hot electrons generated in the interaction of ultrashort intense laser pulses with foil target

2006 ◽  
Vol 55 (11) ◽  
pp. 5899
Author(s):  
Yuan Xiao-Hui ◽  
Li Yu-Tong ◽  
Xu Miao-Hua ◽  
Zheng Zhi-Yuan ◽  
Liang Wen-Xi ◽  
...  
Keyword(s):  
Incidence Angle ◽  
Laser Pulses ◽  
Hot Electrons ◽  
Intense Laser ◽  
Intense Laser Pulses ◽  
Foil Target
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