On the abnormal temperature dependent elastic properties of fused silica irradiated by ultrafast lasers

Materials with thermal-invariant elastic properties of materials are of interest for resonant device frequency and dimensional stability of precision devices. Here, we demonstrate that the temperature coefficient of elasticity (TCE) of amorphous silica can be locally reduced using femtosecond laser irradiation. Notably, a self-organized laser-induced modification shows a decrease of the TCE beyond 50%. The origin of this dramatic decrease is attributed to the presence of sub-micron permanent densified zones within the fine multi-layers structure of the laser-modified zone.