Density variation in fused silica exposed to femtosecond laser

A. Champion, Y. Bellouard

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

2 Citations (Scopus)

Abstract

Fused silica (a-SiO2) exposure to low-energy femtosecond laser pulses leads to interesting effects such as a local increase of etching rate and/or a local increase of refractive index. Up to now the exact modifications occurring in the glass matrix after exposure remains elusive and various hypotheses among which the formation of color centers or of densified zones have been proposed. In the densification model, shorter SiO2 rings form in the glass matrix leading to an enhanced etching rate. In this paper, we investigate quantitatively the amount of volume variation occurring in well-defined laser exposed areas. Our method is based on the deflection of glass cantilevers and hypotheses from classical beam theory. Specifically, 20-mm long cantilevers are fabricated using low-energy femtosecond laser pulses. After chemical etching, the cantilevers are exposed a second time to the same femtosecond laser but only in their upper-half thickness and this time, without a subsequent etching step. We observe micron-scale displacements at the cantilever tips that we use to estimate the volume variation in laser affected zones. Our results not only show that in the regime where nanogratings form (so called type II structures), laser affected zones expand but also provide a quantitative method to estimate the amount of stress as a function of the laser exposure parameters
Original languageEnglish
Title of host publicationFrontiers in ultrafast optics : biomedical, scientific, and industrial application XII, 22-25 january 2012, San Francisco, California
EditorsA. Heisterkamp, M. Meunier, S. Nolte
PublisherSPIE
Pages82470R-
DOIs
Publication statusPublished - 2012
Eventconference; Frontiers in ultrafast optics : biomedical, scientific, and industrial applicationsXII -
Duration: 1 Jan 2012 → …

Publication series

NameProceedings of SPIE
Volume8247
ISSN (Print)0277-786X

Conference

Conferenceconference; Frontiers in ultrafast optics : biomedical, scientific, and industrial applicationsXII
Period1/01/12 → …
OtherFrontiers in ultrafast optics : biomedical, scientific, and industrial applicationsXII

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