Femtosecond Laser Ablation of Titanium and Silicon

2000 ◽  
Author(s):  
Mengqi Ye ◽  
Costas P. Grigoropoulos
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Laser Fluence ◽  
Laser System ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Femtosecond Laser Irradiation ◽  
Nanosecond Laser ◽  
Iccd Camera ◽  
Plume Emission

Abstract Femtosecond laser ablation of titanium and silicon samples has been studied via time-of-flight (TOF), emission spectroscopy and microscopy measurement. Laser pulses of around 100 fs (FWHM) at λ = 800 nm were delivered by a Ti:sapphire femtosecond laser system. A vacuum chamber with a base pressure of 10−7 torr was built for ion TOF measurement. These ion TOF spectra were utilized to determine the velocity distribution of the ejected ions. While nanosecond laser ablation typically generates ions of a few tens of eV, femtosecond laser irradiation even at moderate energy densities can produce energetic ions with energies of up to a few keV. The most probable energy of these fast ions is proportional to the laser fluence. The structure and number of peaks of the TOF spectra varies with the laser fluence. Images of plume emission were captured by an intensified CCD (ICCD) camera. The plume emission spectrum was analyzed by a spectrometer. Laser ablated craters were measured by an interferometric microscope and a scanning electron microscope (SEM). Ablation yield was expressed as a function of laser fluence, and number of shots.

scholarly journals Femtosecond laser ablation of brass: A study of surface morphology and ablation rate

2012 ◽  
Vol 30 (3) ◽  
pp. 473-479 ◽  
Author(s):  
Mohamed E. Shaheen ◽  
Brian J. Fryer
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Surface Morphology ◽  
Fine Particles ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Ambient Air ◽  
Ablation Rate ◽  
Femtosecond Laser Pulses ◽  
Nanosecond Laser

AbstractThe interaction of near infrared femtosecond laser pulses with a Cu based alloy (brass) in ambient air at atmospheric pressure and under different laser conditions was investigated. The effects of laser fluence and number of pulses on surface morphology and ablation rate were studied using scanning electron microscopy (SEM) and optical microscopy. Ablation rates were found to rapidly increase from 83 to 604 nm/pulse in the fluence range 1.14–12.21 J/cm2. At fluence >12.21 J/cm2, ablation rates increased slowly to a maximum (607 nm/pulse at 19.14 J/cm2), and then decreased at fluence higher than 20.47 J/cm2 to 564 nm/pulse at 24.89 J/cm2. Large amounts of ablated material in a form of agglomerated fine particles were observed around the ablation craters as the number of laser pulses and fluence increased. The study of surface morphology shows reduced thermal effects with femtosecond laser ablation in comparison to nanosecond laser ablation at low fluence.

scholarly journals Synthesis of Nanotips Through Femtosecond Laser Ablation of Glass with Assisted Gas

2021 ◽  
Author(s):  
Nikunj Patel
Keyword(s):  
Femtosecond Laser ◽  
Building Materials ◽  
High Vacuum ◽  
Synthesis Method ◽  
Femtosecond Laser Ablation ◽  
Target Surface ◽  
Laser Pulses ◽  
Single Step ◽  
Femtosecond Laser Irradiation ◽  
Ambient Conditions

Nanotips are the key nanostructures for many applications. Until now, the nanotips of only the crystalline materials have been produced via various deposition methods which require sophisticated equipment, high vacuum, and clean room operations. This thesis proposes a single step, rapid synthesis method using femtosecond laser irradiation at megahertz frequency with background flow of nitrogen gas at ambient conditions. Amorphous nanotips are obtained without the use of catalyst. The nanotips grow from highly energetic plasma generated when target is irradiated with laser pulses. The vapor condensates, nanoparticles and droplets from the plasma get deposited back on to the hot target surface where they experience force imbalance due to which the stems for the nanotips growth are initiated. Once the stems are generated, the continuous deposition of vapor condensates [sic] provides building materials to the stems to complete the growth of nanotips. Further study found that the growth of the nanotips is influenced by laser parameters and gas conditions.

Molecular Dynamics Study of Mechanism of Ablation Induced by a Femtosecond Laser Pulse

2003 ◽  
Author(s):  
Changrui Cheng ◽  
Xianfan Xu
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Critical Point ◽  
Change Process ◽  
Femtosecond Laser Ablation ◽  
Md Simulations ◽  
Femtosecond Laser Irradiation ◽  
Transient Temperature

In this work, molecular dynamics (MD) simulations are carried out to study femtosecond laser ablation of a metal, with an emphasis on the understanding of the mechanism of laser ablation. Theoretically, it has been shown that under intense femtosecond laser irradiation, the material can undergo a volumetric phase change process; its temperature can be close to or even above the critical point. MD simulations allow us to determine the transient temperature of the irradiated material as well as the transient thermodynamic state, which explain the mechanisms of femtosecond laser ablation.

Molecular Dynamics Study of Phase Change Mechanisms During Femtosecond Laser Ablation

2004 ◽  
Vol 126 (5) ◽  
pp. 727-734 ◽  
Author(s):  
Xianfan Xu ◽  
Changrui Cheng ◽  
Ihtesham H. Chowdhury
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Phase Change ◽  
Change Process ◽  
Femtosecond Laser Ablation ◽  
Femtosecond Laser Irradiation ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
Phase Change Process

In this work, Molecular Dynamics (MD) simulation is employed to investigate femtosecond laser ablation of copper, with an emphasis on the understanding of the mechanism of phase change during laser ablation. Laser induced heat transfer, melting, surface evaporation, and material ablation are studied. Theoretically, it has been suggested that under intense femtosecond laser irradiation, the material undergoes a volumetric phase change process; its maximum temperature can be close to or even above the thermodynamic critical point. The MD simulations allow us to determine the transient temperature history of the irradiated material and to reveal the exact phase change process, which explains the mechanisms of femtosecond laser ablation. A finite difference calculation is also performed, which is used to compare results of heating and melting prior to a significant amount of material being ablated.

Femtosecond Laser Ablation of Zr55Al10Ni5Cu30 Bulk Metallic Glass

2007 ◽  
Vol 539-543 ◽  
pp. 1951-1954 ◽  
Author(s):  
Tomokazu Sano ◽  
Kengo Takahashi ◽  
Akio Hirose ◽  
Kojiro F. Kobayashi
Keyword(s):  
Laser Ablation ◽  
Metallic Glass ◽  
Femtosecond Laser ◽  
Bulk Metallic Glass ◽  
Pulse Energy ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ablation Depth ◽  
Polished Surface

Dependence of the femtosecond laser ablation depth on the laser pulse energy was investigated for Zr55Al10Ni5Cu30 bulk metallic glass. Investigation of the femtosecond laser ablation of bulk metallic glasses has not been reported. Femtosecond laser pulses (wavelength of 800 nm, pulse width of 100 fs, pulse energies of 2 – 900 μJ) were focused and irradiated on the polished surface of metals in air. The ablation depth of the metallic glass is deeper than that of its crystallized metal at a pulse energy in the strong ablation region. We suggest that the energy loss at grain boundaries of hot electrons which is accelerated by the laser electric field influence the ablation depth in the strong ablation region.

Femtosecond laser ablation of sapphire on different crystallographic facet planes by single and multiple laser pulses irradiation

2010 ◽  
Vol 48 (10) ◽  
pp. 1000-1007 ◽  
Author(s):  
Litao Qi ◽  
Kazuhiro Nishii ◽  
Motohiro Yasui ◽  
Hikoharu Aoki ◽  
Yoshiharu Namba
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses

Femtosecond Laser Ablation of a Single Crystal Superalloy CMSX-4 in Different Environments

2007 ◽  
Vol 546-549 ◽  
pp. 1309-1312 ◽  
Author(s):  
Quan Wen ◽  
Qiang Feng ◽  
Guang Hua Cheng ◽  
Wei Zhao ◽  
Zu Qing Sun
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Single Crystal ◽  
Laser System ◽  
Femtosecond Laser Ablation ◽  
Pulse Number ◽  
Single Crystal Superalloy ◽  
Titanium:Sapphire Laser ◽  
Argon Gas

The femtosecond laser ablation has been investigated on second generation single crystal superalloy CMSX-4 using a commercial titanium:sapphire laser system (λ = 780nm, τ = 120 fs). The ablation thresholds of bulk alloy CMSX-4 have been determined as a function of the pulse number (1, 10, 100, 1000) in air, argon gas and vacuum. The results indicate that the multiple-pulse threshold of this material decreased with increasing the pulse number in all the cases. For the same pulse number, the threshold changed in the descending order: air, vacuum and argon gas. The incubation coefficient in air has been determined: ξ = 0.86 ± 0.03. The preliminary results showed the better quality of femtosecond laser machining of CMSX-4 in vacuum and argon gas than in air.

Rapid Prototyping of Glass Microfluidic Devices using Femtosecond Laser Pulses

2004 ◽  
Vol 820 ◽  
Author(s):  
Myung-Il Park ◽  
Jun Rye Choi ◽  
Mira Park ◽  
Dae Sik Choi ◽  
Sae Chae Jeoung ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Rapid Prototyping ◽  
Laser Fluence ◽  
Femtosecond Laser Ablation ◽  
Microfluidic Devices ◽  
Soda Lime ◽  
Laser Pulses ◽  
Laser Micromachining ◽  
Femtosecond Laser Pulses ◽  
Mems Devices

AbstractLaser micromachining technology with 150 femtosecond pulses is developed to fabricate glass microfluidic devices. A short theoretical analysis of femtosecond laser ablation is reported to characterize the femtosecond laser micromachining. The ablated crater diameter is measured as a function of the number of laser pulses as well as laser fluence. Two different ablation regimes are observed and the transition between the regimes is dependent on both the laser fluence and the number of laser shots. Based on the ablation phenomena described, microfluidic devices are fabricated with commercially available soda lime glasses (76 mm × 26 mm × 1 mm, Knittel Glaser, Germany). In addition to a microchannel for microfluidics, the capillary as well as optical fiber for detecting is integrated on the same substrate. The substrate is successively packaged with a lid slide glass by a thermal direct bonding. The presented developments are suitable for fast turn-around design cycle and inexpensive procedure, which provide rapid prototyping of MEMS devices.

Spectroscopic measurement of plume emission from femtosecond laser ablation

2004 ◽  
Vol 453-454 ◽  
pp. 340-344 ◽  
Author(s):  
Denis Moreau ◽  
O Albert ◽  
R Benzerga ◽  
C Boulmer-Leborgne ◽  
E Millon ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Spectroscopic Measurement ◽  
Plume Emission
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