Open AccessEvolution of hole shape and size during short and ultrashort pulse laser deep drilling
Author(s) -
Sven Döring,
John Szilagyi,
Stefanie Richter,
Felix Zimmermann,
Martin Richardson,
Andreas Tünnermann,
Stefan Nolte
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.027147
Subject(s) - optics , femtosecond , nanosecond , materials science , picosecond , laser drilling , pulse (music) , femtosecond pulse shaping , ultrashort pulse laser , pulse duration , laser , ultrashort pulse , bandwidth limited pulse , drilling , multiphoton intrapulse interference phase scan , physics , detector , metallurgy
A detailed study of the influence of the pulse duration, from the femtosecond to the nanosecond regime, on the evolution of the hole shape and depth during percussion drilling in silicon is presented. Real-time backlight imaging of the hole development is obtained for holes up to 2 mm deep with aspect ratios extending to 25:1. For low pulse energies, the hole-shape and drilling characteristics are similar for femtosecond, picoseconds and nanosecond regimes. At higher pulse energies, ns-pulses exhibit slower average drilling rates but eventually reach greater final depths. The shape of these holes is however dominated by branching and large internal cavities. For ps-pulses, a cylindrical shape is maintained with frequent small bulges on the side-walls. In contrast, fs-pulses cause only a limited number of imperfections on a tapered hole shape.