3D laser microfabrication inside narrow band gap solids like semiconductors will require the use of long wavelength intense pulses. We perform an experimental study of the multiphoton-avalanche absorption yields and thresholds with tightly focused femtosecond laser beams at wavelengths: 1.3μm and 2.2μm. For comparisons, we perform the experiments in two very different materials: silicon (semiconductor, ∼1.1 eV indirect bandgap) and fused silica (dielectric, ∼9 eV direct bandgap). For both materials, we find only moderate differences while the number of photons required to cross the band gap changes from 2 to 3 in silicon and from 10 to 16 in fused silica.

Date Published: 15 March 2013
PDF: 7 pages
Proc. SPIE 8611, Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XIII, 861113 (15 March 2013); doi: 10.1117/12.2003545

Published in SPIE Proceedings Vol. 8611:
Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XIII
Alexander Heisterkamp; Peter R. Herman; Michel Meunier; Stefan Nolte, Editor(s)