Numerical study of the influence of picosecond laser spot size on laser ablation of metal for high laser fluence cases

2017 ◽  
Author(s):  
Yiming Zhang ◽  
Beat Neuenschwander ◽  
Valerio Romano
Keyword(s):  
Laser Ablation ◽  
Laser Fluence ◽  
Numerical Study ◽  
Picosecond Laser ◽  
Spot Size ◽  
Laser Spot ◽  
Laser Spot Size ◽  
High Laser Fluence ◽  
High Laser

Compositionally Gradient Thin Film Deposition by Pulse Laser Ablation under High Gravity

2012 ◽  
Vol 323-325 ◽  
pp. 559-563
Author(s):  
Takashi Nishiyama ◽  
Takashi Kajiwara ◽  
Kunihito Nagayama
Keyword(s):  
Thin Film ◽  
Laser Ablation ◽  
Laser Fluence ◽  
Target Material ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Atomic Fraction ◽  
High Laser Fluence ◽  
High Laser ◽  
Narrow Space

A compositionally graded thin film of Fe/Si was fabricated by a gravity-assisted pulsed laser ablation (GAPLA) system. By this method, a compositionally graded structure along gravity direction was successfully produced under a gravity field of 5,400 G. Systematic experiments were conducted by several parameters, including gravity, distance between target and substrate, and laser fluence in case of typical target material of iron disilicide (FeSi2). We demonstrate that the atomic fraction of Fe, the heavier component of the thin film, showed increasing spatial distribution with the direction of gravity. Relatively high laser fluence as well as a very narrow space between the target and the substrate are found to be essential to the compositionally gradient of thin film.

scholarly journals Laser-induced Forward Transfer Hydrogel Printing: A Defined Route for Highly Controlled Process

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Vladimir Yusupov ◽  
Semyon Churbanov ◽  
Ekaterina Churbanova ◽  
Ksenia Bardakova ◽  
Artem Antoshin ◽  
...  
Keyword(s):  
Laser Fluence ◽  
High Speed ◽  
Laser System ◽  
Spot Size ◽  
Laser Spot ◽  
Turbulent Regime ◽  
Laser Spot Size ◽  
Viscosity Change ◽  
Laser Printing ◽  
Forward Transfer

Laser-induced forward transfer is a versatile, non-contact, and nozzle-free printing technique which has demonstrated high potential for different printing applications with high resolution. In this article, three most widely used hydrogels in bioprinting (2% hyaluronic acid sodium salt, 1% methylcellulose, and 1% sodium alginate) were used to study laser printing processes. For this purpose, the authors applied a laser system based on a pulsed infrared laser (1064 nm wavelength, 8 ns pulse duration, 1 – 5 J/cm2 laser fluence, and 30 μm laser spot size). A high-speed shooting showed that the increase in fluence caused a sequential change in the transfer regimes: No transfer regime, optimal jetting regime with a single droplet transfer, high speed regime, turbulent regime, and plume regime. It was demonstrated that in the optimal jetting regime, which led to printing with single droplets, the size and volume of droplets transferred to the acceptor slide increased almost linearly with the increase of laser fluence. It was also shown that the maintenance of a stable temperature (±2°C) allowed for neglecting the temperature-induced viscosity change of hydrogels. It was determined that under room conditions (20°C, humidity 50%), the hydrogel layer, due to drying processes, decreased with a speed of about 8 μm/min, which could lead to a temporal variation of the transfer process parameters. The authors developed a practical algorithm that allowed quick configuration of the laser printing process on an applied experimental setup. The configuration is provided by the change of the easily tunable parameters: Laser pulse energy, laser spot size, the distance between the donor ribbon and acceptor plate, as well as the thickness of the hydrogel layer on the donor ribbon slide.

Laser Spot Size and Preheating Effects on Alumina Reduction Using Laser Ablation

2020 ◽  
Vol 34 (4) ◽  
pp. 733-740
Author(s):  
Seiya Tanaka ◽  
Shin Yamada ◽  
Kimiya Komurasaki ◽  
Hiroyuki Koizumi
Keyword(s):  
Laser Ablation ◽  
Spot Size ◽  
Laser Spot ◽  
Laser Spot Size

A new method to deconvolute binary mixture in LA-ICP-MS analyses to quantify the composition of phases smaller than the laser spot size

2018 ◽  
Vol 33 (9) ◽  
pp. 1518-1528 ◽  
Author(s):  
Longbo Yang ◽  
Vincent J. van Hinsberg ◽  
Iain M. Samson
Keyword(s):  
Laser Ablation ◽  
Binary Mixture ◽  
Spot Size ◽  
New Method ◽  
Laser Spot ◽  
Laser Spot Size ◽  
Ms Analysis ◽  
Icp Ms ◽  
Data Signal

New quantification strategy to deconvolute the data signal of a binary mixture in laser ablation ICP-MS analysis.

Modelling of the laser spot size dependence of retinal thermal damage

2005 ◽  
Author(s):  
Karl Schulmeister ◽  
Bernhard Seiser ◽  
Florian Edthofer ◽  
David J. Lund
Keyword(s):  
Size Dependence ◽  
Thermal Damage ◽  
Spot Size ◽  
Laser Spot ◽  
Laser Spot Size

scholarly journals Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. Wang ◽  
V. N. Litvinenko ◽  
I. Pinayev ◽  
M. Gaowei ◽  
J. Skaritka ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Electron Beams ◽  
Spot Size ◽  
Laser Spot ◽  
Laser Spot Size ◽  
High Quantum Efficiency ◽  
High Brightness ◽  
High Charge ◽  
Superconducting Radio Frequency ◽  
Long Lifetime

AbstractHigh brightness, high charge electron beams are critical for a number of advanced accelerator applications. The initial emittance of the electron beam, which is determined by the mean transverse energy (MTE) and laser spot size, is one of the most important parameters determining the beam quality. The bialkali photocathodes illuminated by a visible laser have the advantages of high quantum efficiency (QE) and low MTE. Furthermore, Superconducting Radio Frequency (SRF) guns can operate in the continuous wave (CW) mode at high accelerating gradients, e.g. with significant reduction of the laser spot size at the photocathode. Combining the bialkali photocathode with the SRF gun enables generation of high charge, high brightness, and possibly high average current electron beams. However, integrating the high QE semiconductor photocathode into the SRF guns has been challenging. In this article, we report on the development of bialkali photocathodes for successful operation in the SRF gun with months-long lifetime while delivering CW beams with nano-coulomb charge per bunch. This achievement opens a new era for high charge, high brightness CW electron beams.

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