scholarly journals Effect of the laser average power and pulse repetition rate on the spectrum and localization of intense sound produced by an pulsating optical discharge in the air

2017 ◽  
Author(s):  
G. N. Grachev ◽  
I. B. Miroshnichenko ◽  
A. L. Smirnov ◽  
P. A. Statsenko ◽  
V. N. Tischenko ◽  
...  
Keyword(s):  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Average Power ◽  
Pulse Repetition ◽  
Optical Discharge

Spectrum of shock waves produced by an optical discharge at a high laser-pulse repetition rate

2002 ◽  
Vol 32 (4) ◽  
pp. 329-334 ◽  
Author(s):  
V N Tishchenko ◽  
Gennadii N Grachev ◽  
V I Zapryagaev ◽  
A L Smirnov ◽  
A V Sobolev
Keyword(s):  
Laser Pulse ◽  
Shock Waves ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Pulse Repetition ◽  
Optical Discharge ◽  
High Laser ◽  
Laser Pulse Repetition Rate

In vitro study of cataract extraction by bursts of microsecond 1.54-mm laser pulses

2022 ◽  
Vol 52 (1) ◽  
pp. 69-77
Author(s):  
A V Belikov ◽  
S N Smirnov ◽  
Yu N Batov ◽  
A B Gubin ◽  
Yu B Pirozhkov ◽  
...  
Keyword(s):  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Video Recording ◽  
Average Power ◽  
Cataract Extraction ◽  
Pulse Repetition ◽  
Glass Laser ◽  
First Time ◽  
Pulse Spacing

Abstract Laser extraction of a model porcine eye cataract has been performed for the first time in an in vitro experiment using a 1.54-μm Yb,Er : glass laser generating bursts of microsecond pulses. We used effective pulse repetition rates from 36 to 75 Hz and average laser output powers from 3.9 to 5.25 W. The results demonstrate for the first time that, at an effective pulse repetition rate of 45 Hz, burst repetition rate of 15 Hz, three microsecond pulses per burst, and a burst energy from 260 to 265 mJ, the laser step duration in cataract extraction is 130 plusmn; 10 s, which is comparable to the ultrasonic phacoemulsification and laser extraction time in the case of a Nd : YAG laser emitting at 1.44 μm. Acoustometry and high speed video recording of hydroacoustic processes accompanying interaction of water with 1.54-μm radiation from the Yb, Er : glass laser generating bursts of microsecond pulses have made it possible for the first time to detect overlap of hydroacoustic processes at the pulse spacing in bursts reduced to under 700 μs. In the case of overlap of hydroacoustic processes, despite the increase in average power and effective pulse repetition rate, acoustic wave generation is ineffective because pulses propagate through bubbles formed in the water. Laser cataract extraction is shown to be most effective at a lower average power, lower effective pulse repetition rate, and burst pulse spacing of 850 ± 10 μs.

scholarly journals The Influence of the Processing Parameters on the Laser-Ablation of Stainless Steel and Brass during the Engraving by Nanosecond Fiber Laser

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 232
Author(s):  
Luka Hribar ◽  
Peter Gregorčič ◽  
Matej Senegačnik ◽  
Matija Jezeršek
Keyword(s):  
Surface Roughness ◽  
Fiber Laser ◽  
Pulse Duration ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Removal Rate ◽  
Average Power ◽  
Laser Pulses ◽  
Processing Parameters ◽  
Pulse Repetition

In this paper, we investigate the influence of the following parameters: pulse duration, pulse repetition rate, line-to-line and pulse-to-pulse overlaps, and scanning strategy on the ablation of AISI 316L steel and CuZn37 brass with a nanosecond, 1064-nm, Yb fiber laser. The results show that the material removal rate (MRR) increases monotonically with pulse duration up to the characteristic repetition rate (f0) where pulse energy and average power are maximal. The maximum MRR is reached at a repetition rate that is equal or slightly higher as f0. The exact value depends on the correlation between the fluence of the laser pulses and the pulse repetition rate, as well as on the material properties of the sample. The results show that shielding of the laser beam by plasma and ejected material plays an important role in reducing the MRR. The surface roughness is mainly influenced by the line-to-line and the pulse-to-pulse overlaps, where larger overlap leads to lower roughness. Process optimization indicates that while operating with laser processing parameters resulting in the highest MRR, the best ratio between the MRR and surface roughness appears at ~50% overlap of the laser pulses, regardless of the material being processed.

scholarly journals Two Approaches to the Laser-Induced Formation of Au/Ag Bimetallic Nanoparticles in Supercritical Carbon Dioxide

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1553
Author(s):  
Alexey Rybaltovsky ◽  
Evgeniy Epifanov ◽  
Dmitriy Khmelenin ◽  
Andrey Shubny ◽  
Yuriy Zavorotny ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Ag Nanoparticles ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Bimetallic Nanoparticles ◽  
Side Wall ◽  
Pulse Repetition ◽  
Gold Core ◽  
Supercritical Carbon

Two approaches are proposed for the synthesis of bimetallic Au/Ag nanoparticles, using the pulsed laser ablation of a target consisting of gold and silver plates in a medium of supercritical carbon dioxide. The differences between the two approaches related to the field of “green chemistry” are in the use of different geometric configurations and different laser sources when carrying out the experiments. In the first configuration, the Ag and Au targets are placed side-by-side vertically on the side wall of a high-pressure reactor and the ablation of the target plates occurs alternately with a stationary “wide” horizontal beam with a laser pulse repetition rate of 50 Hz. In the second configuration, the targets are placed horizontally at the bottom of a reactor and the ablation of their parts is carried out by scanning from above with a vertical “narrow” laser beam with a pulse repetition rate of 60 kHz. The possibility of obtaining Ag/Au alloy nanoparticles is demonstrated using the first configuration, while the possibility of obtaining “core–shell” bimetallic Au/Ag nanoparticles with a gold core and a silver shell is demonstrated using the second configuration. A simple model is proposed to explain the obtained results.

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