Optimized energy coupling at ultrafast laser-irradiated metal surfaces by tailoring intensity envelopes: Consequences for material removal from Al samples

Journal Article · Fri Dec 01 00:00:00 EST 2006 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.74.224106· OSTI ID:20853958

Colombier, J P; Audouard, E; Stoian, R ^[1]; Combis, P ^[2]; Rosenfeld, A; Hertel, I V ^[3]

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1. Laboratoire TSI (UMR 5516 CNRS), Universite Jean Monnet, 42000 Saint Etienne (France)
2. CEA/DAM Ile de France, Dept. de Physique Theorique et Appliquee, 91680 Bruyeres-le-Chatel (France)
3. Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin (Germany)

We present results describing the efficiency of energy coupling in laser-irradiated metallic surfaces by ultrashort laser pulses with different intensity envelopes. Subsequently, we discuss probable thermodynamic paths for material ejection under the laser action. Ion and neutral emission from the excited sample is used as a sensitive method to probe the efficiency of energy deposition in the material. With support from numerical simulations of the hydrodynamic advance of the excited matter, consequences of optimized energy coupling relevant for applications in material processing are revealed. Despite the reduced sensitivity to intensity-dependent effects for linear materials, the overall absorption efficiency can be elevated if the proper conditions of density and temperature are met for the expanding material layers. In this respect, short sub-ps single pulse irradiation is compared with picosecond sequences. We show that in particular irradiation regimes, characterized by fluences superior to the material removal threshold, laser energy delivery extending on several picoseconds leads to significant superheating of the superficial layers as compared to femtosecond irradiation and to a swift acceleration of the emitted particles. Subsequently, the lifetime of the post-irradiation liquid layer is diminished, which, in turn, translates into a reduction in droplet ejection. In contrast, short pulse irradiation at moderate fluences generates a higher quantity of removed material that is ejected in a dense mixture of gas and liquid-phase particulates.

• OSTI ID: 20853958
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 74, Issue 22; Other Information: DOI: 10.1103/PhysRevB.74.224106; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ABLATION
ACCELERATION
ALUMINIUM
COMPUTERIZED SIMULATION
COUPLING
DENSITY
DROPLETS
HYDRODYNAMICS
ION EMISSION
LAYERS
LIQUIDS
PARTICULATES
PHASE TRANSFORMATIONS
PULSED IRRADIATION
PULSES
SUPERHEATING
SURFACES
THERMODYNAMICS