Long-Time Feedback in the Formation of Self-Organized Nanostructures upon Multipulse Femtosecond Laser Ablation

Journal Article · Fri Oct 08 00:00:00 EDT 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3507133· OSTI ID:21426596

Reif, Juergen; Varlamova, Olga ^[1]; Bounhalli, Mourad ^[1]; Arguirov, Tzanimir ^[2]

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1. Brandenburgische Technische Universitaet (BTU) Cottbus Universitaetsstr. 1, 03046 Cottbus (Germany)
2. Cottbus JointLab, Erich-Weinert-Str. 1, 03046 Cottbus (Germany)

The self-organization feedback in nanostructures (ripples) formation upon femtosecond laser ablation is investigated in detail, with particular emphasis on its dynamics. We study the influence of time separation between successive pulses on both the size and complexity of the nanostructures and on the size of the modified surface area. By varying the pulse separation between 1 ms and 1 s (rep. rate between 1 kHz and 1 Hz), we find that both modified area as well as pattern feature size and complexity decrease with increasing pulse-to-pulse delay, indicating that the coupling efficiency between laser and target increases with increasing repetition rate. Structure formation resulting from surface instability, induced by the laser impact, suggests that the laser-induced instability results in a transient increase of absorption probability, slowly decaying in time. The stronger this transient absorption, the better is the coupling for the succeeding pulse, thus resulting in a positive feedback. Experimental results indicate that the lifetime of the feedback can last up to one second and longer.In addition, a persisting modulated spatial modification of crystalline properties is observed well beyond the ablation spot, though no apparent influence on surface morphology is seen. Mapping the band-to-band photoluminescence from silicon indicates a dramatic increase of non-radiative recombination compared to unaffected material.

• OSTI ID: 21426596
• Journal Information: AIP Conference Proceedings, Vol. 1278, Issue 1; Conference: International symposium on high power laser ablation 2010, Santa Fe, NM (United States), 18-22 Apr 2010; Other Information: DOI: 10.1063/1.3507133; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
36 MATERIALS SCIENCE
ABLATION
ABSORPTION
FEEDBACK
KHZ RANGE
LASER RADIATION
LASERS
MODIFICATIONS
MORPHOLOGY
NANOSTRUCTURES
PHOTOLUMINESCENCE
PULSED IRRADIATION
PULSES
SILICON
SURFACE AREA
SURFACES
TRANSIENTS
X-RAY DIFFRACTION
COHERENT SCATTERING
DIFFRACTION
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION
FREQUENCY RANGE
IRRADIATION
LUMINESCENCE
PHOTON EMISSION
RADIATIONS
SCATTERING
SEMIMETALS
SORPTION
SURFACE PROPERTIES