ИСТИНА

Chalcogenide vitreous semiconductors (ChVS) have potential for telecommunications and infrared (IR) polarization optics, being transparent with high refractive index in the near IR range, and possessing possibilities of photostructural transformations and laser-induced periodic surface structures (LIPSS) formation with optical anisotropy on their surface. In this work, femtosecond laser pulses (515 nm, 300 fs, fluence 8 – 270 mJ/cm2, frequency up to 2 kHz) were used to produce various LIPSS types on the surface of 1-μm-thick ChVS (As2S3, As2Se3 and As50Se50) films. The obtained LIPSS were in the form of one-dimensional gratings with a period from 500 to 170 nm and a depth of up to 100 nm, or hierarchical structures containing two mutually orthogonal gratings with different periods. The possibility to control the optical anisotropy of LIPSS formed on the ChVS by changing the number and fluence of the laser pulses is demonstrated: the optical retardance value in the LIPSS varies from 0 to 30 nm for one layer of ChVS film. The possibility of increasing the optical retardance using layer-by-layer deposition of ChVS with subsequent LIPSS formation on each layer is presented. A correlation is demonstrated between the photoluminescence intensity of laser-modified As2S3 films and the concentration of defects in the form of homopolar bonds in them, while paramagnetic defects in the form of dangling sulfur bonds are shown to not contribute to the luminescence. The work was supported by the Russian Science Foundation (project 22-19-00035-П), https://rscf.ru/en/project/22-19-00035/.