Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses

TL;DR

This study demonstrates that intense laser irradiation induces a permanent radial birefringence in silver-doped glasses, enabling spin-to-orbital angular momentum conversion, with the effect modeled as thermally-induced stress.

Contribution

It reports the first observation of laser-induced radial birefringence in silver-doped glasses and links it to thermally-induced stress mechanisms.

Findings

Laser irradiation creates permanent radial birefringence.

The birefringence enables spin-to-orbital angular momentum conversion.

The effect is modeled as resulting from thermally-induced stresses.

Abstract

Samples of Ag$^+$/Na$^{+}$ ion-exchanged glass that have been subject to intense laser irradiation may develop novel optical properties, as a consequence of the formation of patterns of silver nanoparticles and other structures. Here, we report the observation of a laser-induced permanent transverse birefringence, with the optical axis forming a radial pattern, as revealed by the spin-to-orbital angular momentum conversion occurring in a probe light beam. The birefringence pattern can be modeled well as resulting from thermally-induced stresses arising in the silver-doped glass during laser exposure, although the actual mechanism leading to the permanent anisotropy is probably more complex.