Optimizing controlled laser cutting of hard tissue (bone)

2018 ◽  
Vol 66 (12) ◽  
pp. 1072-1082 ◽  
Author(s):  
Lina M. Beltran Bernal ◽  
Iris T. Schmidt ◽  
Nikola Vulin ◽  
Jonas Widmer ◽  
Jess G. Snedeker ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Laser Cutting ◽  
Laser Surgery ◽  
Healing Process ◽  
Ablation Rate ◽  
Movement Speed ◽  
Lateral Movement ◽  
Hard Tissue ◽  
Robot Assisted ◽  
Bone Surgery

Abstract Conventional bone surgery leads to unwanted damage to the surrounding tissues and a slow healing process for the patients. Additionally, physicians are not able to perform free cutting shapes due to the limitations of available systems. These issues can be overcome by robot-assisted contactless laser surgery since it provides less mechanical stress, allows precise functional cuts, and leads to faster healing. The remaining drawback of laser surgery is the low ablation rate that is not yet competitive with conventional mechanical piezo-osteotomes. Therefore, we aim at maximizing the efficiency in hard tissue laser ablation by optimizing the lateral movement speed for different irrigation conditions. The results of this study show a non-linear relationship between cutting rates, speeds, and depths that should be critically considered for integration in robotic laser surgery.

scholarly journals Ablation of Bone Tissue by Femtosecond Laser: A Path to High-Resolution Bone Surgery

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2429
Author(s):  
Laura Gemini ◽  
Samy Al-Bourgol ◽  
Guillaume Machinet ◽  
Aboubakr Bakkali ◽  
Marc Fauçon ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Bone Tissue ◽  
Laser Pulses ◽  
Ablation Rate ◽  
Biological Tissues ◽  
Thermal Loads ◽  
Bone Surgery ◽  
Fs Laser ◽  
Laser Sources ◽  
Fresh Bone

Femtosecond lasers allow for high-precision, high-quality ablation of biological tissues thanks to their capability of minimizing the thermal loads into the irradiated material. Nevertheless, reported ablation rates remain still too limited to enable their exploitation on a clinical level. This study demonstrates the possibility to upscale the process of fs laser ablation of bone tissue by employing industrially available fs laser sources. A comprehensive parametric study is presented in order to optimize the bone tissue ablation rate while maintaining the tissue health by avoiding excessive thermal loads. Three different absorption regimes are investigated by employing fs laser sources at 1030 nm, 515 nm and 343 nm. The main differences in the three different wavelength regimes are discussed by comparing the evolution of the ablation rate and the calcination degree of the laser ablated tissue. The maximum of the ablation rate is obtained in the visible regime of absorption where a maximum value of 0.66 mm3/s is obtained on a non-calcined tissue for the lowest laser repetition rate and the lowest spatial overlap between successive laser pulses. In this regime, the hemoglobin present in the fresh bone tissue is the main chromophore involved in the absorption process. To the best of our knowledge, this is the highest ablation rate obtained on porcine femur upon fs laser ablation.

scholarly journals Thermodynamic Investigations on the Laser Ablation Rate of Silicon over Five Fluence Decades

2013 ◽  
Vol 41 ◽  
pp. 640-649 ◽  
Author(s):  
V. Schütz ◽  
U. Stute ◽  
A. Horn
Keyword(s):  
Laser Ablation ◽  
Ablation Rate

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.

Micromachining of Metals, Alloys and Ceramics by Picosecond Laser Ablation

2008 ◽  
Author(s):  
Wenqian Hu ◽  
Galen B. King ◽  
Yung C. Shin
Keyword(s):  
Electron Microscope ◽  
Laser Ablation ◽  
Picosecond Laser ◽  
Ablation Rate ◽  
Optical Microscope ◽  
Recast Layer ◽  
Laser Machining ◽  
Percussion Drilling ◽  
Scanning Electron

Microhole drilling and microstructure machining with a picosecond (ps) Nd:YVO4 laser (pulse duration of 10 ps) in metals, alloys and ceramics are reported. Blind and through microholes were drilled by percussion drilling as well as trepanning drilling. The diameters of the holes were in the range from 20 μm to 1000 μm. Microfeatures were machined and the flexibility of ps laser machining was demonstrated. The quality of drilled holes, e.g., recast layer, microcrack and conicity, and that of the microstructures, were investigated by optical microscope, surface profilometer, or scanning electron microscope (SEM). Ps laser ablation rate was investigated by experiments as well as a simplified laser ablation model.

Excimer laser ablation of aluminum: influence of spot size on ablation rate

Laser Physics ◽  
2016 ◽  
Vol 26 (11) ◽  
pp. 116102 ◽  
Author(s):  
M E Shaheen ◽  
J E Gagnon ◽  
B J Fryer
Keyword(s):  
Laser Ablation ◽  
Excimer Laser ◽  
Ablation Rate ◽  
Spot Size ◽  
Excimer Laser Ablation

Modeling for Chemical-Etching Enhanced Pulsed Laser Ablation

2019 ◽  
Author(s):  
Xing Zhang ◽  
Bo Mao ◽  
Rebecca Histed ◽  
Yiliang Liao
Keyword(s):  
Laser Ablation ◽  
Chemical Etching ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Ablation Rate ◽  
Temperature Dependent ◽  
Laser Shock Processing ◽  
Active Liquid ◽  
Shock Processing

Abstract Pulsed laser ablation (PLA) under active liquid confinement, also known as chemical etching enhanced pulsed laser ablation (CE-PLA), has emerged as a novel laser processing methodology, which breaks the current major limitation in underwater PLA caused by the breakdown plasma and effectively improves the efficiencies of underwater PLA-based processes, such as laser-assisted nano-/micro-machining and laser shock processing. Despite of experimental efforts, little attention has been paid on CE-PLA process modeling. In this study, an extended two-temperature model is proposed to predict the temporal/spatial evolution of the electron-lattice temperature and the ablation rate in the CE-PLA process. The model is developed with considerations on the temperature-dependent electronic thermal properties and optical properties of the target material. The ablation rate is formulated by incorporating the mutual promotion between ablation and etching processes. The simulation results are validated by the experimental data of CE-PLA of zinc under the liquid confinement of hydrogen peroxide.

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.

Enhanced Laser Shock by an Active Liquid Confinement—Hydrogen Peroxide

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Yiliang Liao ◽  
Yingling Yang ◽  
Gary J. Cheng
Keyword(s):  
Hydrogen Peroxide ◽  
Laser Ablation ◽  
Pulse Laser Ablation ◽  
Ablation Rate ◽  
Laser Shock ◽  
Active Liquid ◽  
Pulsed Laser Processing ◽  
Shock Peening ◽  
Fast Chemical ◽  
Alloy 6061

This letter investigates a unique process to generate enhanced laser shock by applying an active liquid confinement—hydrogen peroxide (H2O2). The mechanism of fast chemical etching-assisted laser ablation is proposed. As a result, comparing with utilizing water as confinement, the efficiency of laser shock peening (LSP) of aluminum alloy 6061 with an active liquid confinement is improved by 150%, and the ablation rate of pulse laser ablation (PLA) of zinc is enhanced by 300%. This method breaks the major limitation of underwater pulsed laser processing caused by the breakdown plasma, with additional mechanisms to generate higher ablation rate and shock pressure under the same laser intensities.

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