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.

Ablation of Si and Ge Using UV Femtosecond Laser Pulses

1995 ◽  
Vol 397 ◽  
Author(s):  
G. Herbst ◽  
M. Steiner ◽  
G. Marowsky ◽  
E. Matthias
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Material Removal ◽  
Laser Pulses ◽  
Ablation Rate ◽  
Femtosecond Laser Pulses ◽  
Bond Breaking ◽  
Intensity Enhancement ◽  
Silicon And Germanium

ABSTRACTLaser ablation of silicon and germanium was carried out in moderate vacuum with l00fs to 400fs pulses at 248nm and intensities up to 3x1013 W/cm2. Evidence for non-thermal material removal was found. Imaged multishot ablation patterns display the intensity dependent self-structuring effect, forming well-known columnar structures. It is shown that continued irradiation of these structures eventually results in comparatively clean ablation. An increase of ablation rate with depth was observed. The reason is an intensity enhancement inside the pits by reflective focussing to a level where bond-breaking takes place. Furthermore, it was noticed that ablation contours can be significantly improved by electrically grounding the target.

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 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 Nano-Fabrication And Its Biomedical Applications

2021 ◽  
Author(s):  
Amirhossein Tavangar
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Biomedical Application ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Femtosecond Laser Pulses ◽  
Device Fabrication ◽  
Ambient Conditions ◽  
Wide Range ◽  
Multiple Pulses

This dissertation aims to develop a new technique for fabrication of three-dimensional (3-D) interwoven nanofibrous platforms using femtosecond laser ablation of solids in ambient conditions. In the first part, the mechanism of ablation of solids by multiple femtosecond laser pulses in ambient air is described in an explicit analytical form. The formulas for evaporation rates and the number of ablated particles for laser ablation by multiple pulses as a function of laser parameters, background gas, and material properties are predicted and compared to experimental results. Later, the formation mechanism of the nanofibrous structures during laser ablation of targets in the presence of air is discussed. The results indicate that femtosecond laser ablation of solids at air background yields crystalline nanostructures. It’s also shown that this technique allows synthesis of 3-D nanostructures on a wide range of materials including synthetic and natural materials. Later, potential practice of the proposed technique for integration of nanostructures on transparent platforms as well as inside microstructures toward device fabrication is investigated. Presented studies show that integrated nanostructure inside microchannels can be fabricated in one single step using this technique. Finally, to address the potential use of the nanostructures for biomedical application, several studies are performed to evaluate the bioactivity and biocompatibility of the nanostructures. The fabricated nanostructures incorporate the functions of 3-D nano-scaled topography and modified chemical properties to improve osseointegration, while at the same time leaving space for delivering other functional agents.

scholarly journals Femtosecond Laser Nano-Fabrication And Its Biomedical Applications

2021 ◽  
Author(s):  
Amirhossein Tavangar
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Biomedical Application ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Femtosecond Laser Pulses ◽  
Device Fabrication ◽  
Ambient Conditions ◽  
Wide Range ◽  
Multiple Pulses

This dissertation aims to develop a new technique for fabrication of three-dimensional (3-D) interwoven nanofibrous platforms using femtosecond laser ablation of solids in ambient conditions. In the first part, the mechanism of ablation of solids by multiple femtosecond laser pulses in ambient air is described in an explicit analytical form. The formulas for evaporation rates and the number of ablated particles for laser ablation by multiple pulses as a function of laser parameters, background gas, and material properties are predicted and compared to experimental results. Later, the formation mechanism of the nanofibrous structures during laser ablation of targets in the presence of air is discussed. The results indicate that femtosecond laser ablation of solids at air background yields crystalline nanostructures. It’s also shown that this technique allows synthesis of 3-D nanostructures on a wide range of materials including synthetic and natural materials. Later, potential practice of the proposed technique for integration of nanostructures on transparent platforms as well as inside microstructures toward device fabrication is investigated. Presented studies show that integrated nanostructure inside microchannels can be fabricated in one single step using this technique. Finally, to address the potential use of the nanostructures for biomedical application, several studies are performed to evaluate the bioactivity and biocompatibility of the nanostructures. The fabricated nanostructures incorporate the functions of 3-D nano-scaled topography and modified chemical properties to improve osseointegration, while at the same time leaving space for delivering other functional agents.

scholarly journals A study of substrate temperature distribution during ultrashort laser ablation of bulk copper

2007 ◽  
Vol 25 (1) ◽  
pp. 155-159 ◽  
Author(s):  
Y.C. LAM ◽  
D.V. TRAN ◽  
H.Y. ZHENG
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Thermal Power ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Laser Materials ◽  
Laser Ablation Process ◽  
Copper Specimen ◽  
Ultrashort Laser

With the aid of an infrared thermograph technique, we directly observed the temperature variation across a bulk copper specimen as it was being ablated by multiple femtosecond laser pulses. Combining the experimental results with simulations, we quantified the deposited thermal power into the copper specimen during the femtosecond laser ablation process. A substantial amount of thermal power (more than 50%) was deposited in the copper specimen, implying that thermal effect can be significant in femtosecond laser materials processing in spite of its ultrashort pulse duration.

Femtosecond laser ablation of Zn in air and ethanol: effect of fluence on the surface morphology, ablated area, ablation rate and hardness

2021 ◽  
Vol 127 (4) ◽  
Author(s):  
Shazia Bashir ◽  
Muhammad Shahid Rafique ◽  
Ali Asghar Ajami ◽  
Chandra Sekher Nathala ◽  
Wolfgang Husinsky ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Surface Morphology ◽  
Femtosecond Laser Ablation ◽  
Ablation Rate ◽  
Ethanol Effect

Multipulse irradiation of silicon by femtosecond laser pulses: Variation of surface morphology

2012 ◽  
Vol 258 (8) ◽  
pp. 3589-3597 ◽  
Author(s):  
S. Lugomer ◽  
A. Maksimović ◽  
B. Farkas ◽  
Z. Geretovszky ◽  
T. Szörényi ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Surface Morphology ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

scholarly journals Study of the formation of 3-D titania nanofibrous structure by MHz femtosecond laser in ambient air

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Deposition Rate ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Experimental Results ◽  
Laser Parameters ◽  
Nanofibrous Structure ◽  
Titania Nanostructures ◽  
Multiple Pulses

In this study, we describe the formation mechanism of web-like three-dimensional (3-D) titania nanofibrous structures during femtosecond laser ablation of titanium (Ti) targets in the presence of background air. First, we demonstrate the mechanism of ablation of Ti targets by multiple femtosecond laser pulses at ambient air in an explicit analytical form. The formulas for evaporation rates and the number of ablated particles, which is analogous to the deposition rate of the synthesized nanofibers, for the ablation by a single pulse and multiple pulses as a function of laser parameters, background gas, and material properties are predicted and compared to experimental results. Afterwards, the formation of nanofibrous structures is demonstrated by applying an existing simplified kinetic model to Ti targets and ambient conditions. The predicted theory provides nanofiber diameter dependency with the combination of laser parameters, target properties, and ambient gas characteristics. Experimental studies are then performed on titania nanofibrous structures synthesized by laser ablation of Ti targets using MHz repletion-rate femtosecond laser at ambient air. The models' predictions are then compared with the experimental results, where nanostructures with different morphologies are manufactured by altering laser parameters. Our results indicate that femtosecond laser ablation of Ti targets at air background yields crystalline titania nanostructures. The formation of crystalline titania nanostructures is preceded b thermal mechanism of nucleation and growth. The results point out that laser pulse repetition and dwell time can control the density, size, and pore size of the engineered nanofibrous structure. As the deposition rate of nanostructures is analogous to the ablation rate of the target, higher density of nanofibrous structure is seen at greater laser fluences. The predicted theory can be applied to predict ablation mechanism and nanofiber formation of different materials.

scholarly journals Laser ablation of silicon with THz bursts of femtosecond pulses: an experimental and theoretical investigation

2021 ◽  
Author(s):  
Caterina Gaudiuso ◽  
Pavel N. Terekhin ◽  
Annalisa Volpe ◽  
Stefan Nolte ◽  
Bärbel Rethfeld ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Thermal Load ◽  
Laser Pulses ◽  
Ablation Rate ◽  
Pulse Mode ◽  
Femtosecond Laser Pulses ◽  
Photon Absorption ◽  
Burst Frequency ◽  
Two Photon Absorption ◽  
Theoretical Investigations

Abstract In this work, we performed an experimental investigation supported by a theoretical analysis, to improve knowledge on the laser ablation of silicon with THz bursts of femtosecond laser pulses. Laser ablated craters have been created using 200 fs pulses at a wavelength of 1030 nm on silicon samples systematically varying the burst features and comparing to the Normal Pulse Mode (NPM). Using bursts in general allowed reducing the thermal load to the material, however, at the expense of the ablation rate. The higher the number of pulses in the bursts and the lower the intra-burst frequency, the lower is the specific ablation rate. However, bursts at 2 THz led to a higher specific ablation rate compared to NPM, in a narrow window of parameters. Theoretical investigations based on the numerical solution of the density-dependent two temperature model revealed that lower lattice temperatures are reached with more pulses and lower intra-burst frequencies, thus supporting the experimental evidence of the lower thermal load in Burst Mode (BM). This is ascribed to the weaker transient drop of reflectivity, which suggests that with bursts less energy is transferred from the laser to the material. This also explains the trends of the specific ablation rates. Moreover, we found that two-photon absorption plays a fundamental role during BM processing in the THz frequency range.

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