  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.
