Sub-wavelength self-organization of chalcogenide glass by direct laser writing

Chalcogenide glasses (GhGs) are quoted as a key material for the development of infrared technologies due to its unique optical properties. The right choice of processing technique is crucial to reach progress in this field, especially when achieving the nanoscale, to further comprise new functionalities to ChGs. Herein, we demonstrated the sub-wavelength self-organization of ChG with hierarchical nano/micro control by using ultrafast laser processing, representing an important step towards the fabrication of photonic devices of tailored architectures. Particularly, those findings are demonstrated through laser induced forward transfer with femtosecond pulses applied to As₂S₃ thin films, which enabled the controlled deposition of nanostructures within a micrometric region (with resolution on the order of 3 μm). The self-organized patterns exhibits periodicity with subwavelength dimensions on the order of λ/4, with λ ∼800 nm. In the best of our knowledge, the investigation addressed herein correspond to the first demonstration of self- organization of ChG using direct laser writing, extending the applicability of the method for materials nanostructuring.