Crossing the threshold of ultrafast laser writing in bulk silicon.
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
An important challenge in the field of three-dimensional ultrafast laser processing is to achieve permanent modifications in the bulk of silicon and narrow-gap materials. Recent attempts by increasing the energy of infrared ultrashort pulses have simply failed. Here, we establish that it is because focusing with a maximum numerical aperture of about 1.5 with conventional schemes does not allow overcoming strong nonlinear and plasma effects in the pre-focal region. We circumvent this limitation by exploiting solid-immersion focusing, in analogy to techniques applied in advanced microscopy and lithography. By creating the conditions for an interaction with an extreme numerical aperture near 3 in a perfect spherical sample, repeatable femtosecond optical breakdown and controllable refractive index modifications are achieved inside silicon. This opens the door to the direct writing of three-dimensional monolithic devices for silicon photonics. It also provides perspectives for new strong-field physics and warm-dense-matter plasma experiments.Ultrafast laser processing is a versatile three-dimensional photonic structuring method but it has been limited to wide band gap materials like glasses. Here, Chanal et al. demonstrate direct refractive-index modification in the bulk of silicon by extreme localization of the energy deposition.
published proceedings
Nat Commun
altmetric score
19.5
author list (cited authors)
Chanal, M., Fedorov, V. Y., Chambonneau, M., Clady, R., Tzortzakis, S., & Grojo, D.
citation count
57
complete list of authors
Chanal, Margaux||Fedorov, Vladimir Yu||Chambonneau, Maxime||Clady, Raphaƫl||Tzortzakis, Stelios||Grojo, David