Structural relaxation phenomena in silicate glasses modified by irradiation with femtosecond laser pulses

Thomas Seuthe,Lothar Wondraczek,Jörn Bonse,Moritz Grehn,Alexandre Mermillod-Blondin,Markus Eberstein

doi:10.1038/srep43815

Abstract

Structural relaxation phenomena in binary and multicomponent lithium silicate glasses were studied upon irradiation with femtosecond (fs) laser pulses (800 nm central wavelength, 130 fs pulse duration) and subsequent thermal annealing experiments. Depending on the annealing temperature, micro-Raman spectroscopy analyses evidenced different relaxation behaviours, associated to bridging and non-bridging oxygen structures present in the glass network. The results indicate that the mobility of lithium ions is an important factor during the glass modification with fs-laser pulses. Quantitative phase contrast imaging (spatial light interference microscopy) revealed that these fs-laser induced structural modifications are closely related to local changes in the refractive index of the material. The results establish a promising strategy for tailoring fs-laser sensitivity of glasses through structural mobility.

Highlights

Selected for this study as they both exhibit characteristic changes in the local Si-O-Si bond angles and in the Si-O* bond strengths upon fs-laser induced material modification[22]
The black solid lines represent specific Raman bands associated to individual stretching and bending motions of specific sub-structures in silicate glasses
In the Supplementary Information to this article we provide a study of the relaxation dynamics upon annealing of laser-induced structural modifications above Tg (α-relaxation25) based on the analysis of band B

Summary

Introduction

Selected for this study as they both exhibit characteristic changes in the local Si-O-Si bond angles and in the Si-O* bond strengths upon fs-laser induced material modification[22]. Those modifications can be directly probed via micro Raman spectroscopy and allow a qualification of the structural state of the material. Different annealing behaviours (associated with α-and β-relaxations processes) were identified above and below Tg. Complementary quantitative phase contrast imaging measurements reveal the correlation between structural arrangement and refractive index

Methods

Results

Conclusion