Micromachining of Transparent, Semiconducting and Metallic Substrates Using Femtosecond Laser Beams

AbstractThe study of microstructure evolution in additive manufacturing of metals would be aided by knowing the thermal history. Since temperature measurements beneath the surface are difficult, estimates are obtained from computational thermo-mechanical models calibrated against traces left in the sample revealed after etching, such as the trace of the melt pool boundary. Here we examine the question of how reliable thermal histories computed from a model that reproduces the melt pool trace are. To this end, we perform experiments in which one of two different laser beams moves with constant velocity and power over a substrate of 17-4PH SS or Ti-6Al-4V, with low enough power to avoid generating a keyhole. We find that thermal histories appear to be reliably computed provided that (a) the power density distribution of the laser beam over the substrate is well characterized, and (b) convective heat transport effects are accounted for. Poor control of the laser beam leads to potentially multiple three-dimensional melt pool shapes compatible with the melt pool trace, and therefore to multiple potential thermal histories. Ignoring convective effects leads to results that are inconsistent with experiments, even for the mild melt pools here.

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The role of standing wave in the generation of hot electrons by femtosecond laser beams incident on dense ionized target

Physics of Plasmas ◽

10.1063/5.0031555 ◽

2021 ◽

Vol 28 (2) ◽

pp. 023107

Author(s):

R. Babjak ◽

J. Psikal

Keyword(s):

Femtosecond Laser ◽

Standing Wave ◽

Hot Electrons ◽

Laser Beams

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High spectral energy density supercontinuum generation in fused silica by interfering two femtosecond laser beams

Journal of Optics ◽

10.1088/2040-8986/ab173d ◽

2019 ◽

Vol 21 (6) ◽

pp. 065501

Author(s):

Dongwei Li ◽

Lanzhi Zhang ◽

Tingting Xi ◽

Zuoqiang Hao

Keyword(s):

Energy Density ◽

Femtosecond Laser ◽

Supercontinuum Generation ◽

Fused Silica ◽

Laser Beams ◽

Spectral Energy ◽

Spectral Energy Density

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Femtosecond laser absorption, heat propagation, and damage threshold analysis for Au coating on metallic substrates

Applied Surface Science ◽

10.1016/j.apsusc.2017.05.230 ◽

2017 ◽

Vol 422 ◽

pp. 295-303 ◽

Cited By ~ 3

Author(s):

Anastassiya Suslova ◽

Ahmed Hassanein

Keyword(s):

Femtosecond Laser ◽

Damage Threshold ◽

Heat Propagation ◽

Threshold Analysis ◽

Metallic Substrates ◽

Laser Absorption

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Temporally shaped Laguerre–Gaussian femtosecond laser beams

Applied Optics ◽

10.1364/ao.57.003624 ◽

2018 ◽

Vol 57 (13) ◽

pp. 3624 ◽

Cited By ~ 1

Author(s):

Tom Bolze ◽

Patrick Nuernberger

Keyword(s):

Femtosecond Laser ◽

Laser Beams

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Maskless formation of uniform subwavelength periodic surface structures by double temporally-delayed femtosecond laser beams

Applied Surface Science ◽

10.1016/j.apsusc.2018.12.029 ◽

2019 ◽

Vol 471 ◽

pp. 516-520 ◽

Cited By ~ 13

Author(s):

Sohail A. Jalil ◽

Jianjun Yang ◽

Mohamed ElKabbash ◽

Subhash C. Singh ◽

Chunlei Guo

Keyword(s):

Femtosecond Laser ◽

Surface Structures ◽

Laser Beams ◽

Periodic Surface

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Stimulated Raman Microscopy Implemented by Three Femtosecond Laser Sources

EPJ Web of Conferences ◽

10.1051/epjconf/202125506003 ◽

2021 ◽

Vol 255 ◽

pp. 06003

Author(s):

Rajeev Ranjan ◽

Maria Antonietta Ferrara ◽

Luigi Sirleto

Keyword(s):

Femtosecond Laser ◽

Stimulated Raman Scattering ◽

Second Harmonic ◽

Laser Beams ◽

Raman Gain ◽

Harmonic Generator ◽

Second Harmonic Generator ◽

Laser Sources ◽

Fingerprint Region ◽

Stimulated Raman

In this work, the implementation of a femtosecond Stimulated Raman Scattering microscope, equipped with three femtosecond laser sources: a Titanium-Sapphire (Ti:Sa), an optical parametric oscillator (OPO), and a second harmonic generator (SHG); is presented. Our microscope is designed so that it can cover all the regions of Raman spectra, taking advantage of two possible laser combinations. The first, Ti:Sa and OPO laser beams, which cover the C-H region (>2800 cm-1 ) in stimulated Raman gain (SRG) modality, whereas the second, Ti:Sa and SHG laser beams, covering the C-H region and the fingerprint region in stimulated Raman losses (SRL) modality. The successful realization of the microscope is demonstrated, reporting images of polystyrene beads using both SRL and SRG modalities.

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