Transient Study On The Pore Structure Evolution Of Femtosecond Laser Ablation Of Chalcogenide Glass

Chalcogenide glasses(Ch Gs)can be used in many fields such as optical communication,optical sensing,and optical recording due to their wide transparent range,high refractive index,high nonlinear optical coefficient,and high photosensitivity.In addition,the realization of nanostructures on the surface of the material or the preparation of nanopore arrays and nanogratings and the like having a high refractive index play a important role in the preparation of functional devices in future optical systems.Among these manufacturing technologies,femtosecond pulsed laser has received extensive attention in the field of micromachining due to their strong compatibility and "cold processing" of materials,and this technique developed rapidly.Femtosecond laser has been used to make 3D holographic recordings,gratings and optical waveguides.In addition,the processes of generating different morphological structures on the materials surfaces radiated by femtosecond pulsed laser were complicated,involving multiple interactions between light and matter.So far,there were few researches have been done on the surface morphology evolution of femtosecond laser induced arsenic sulfide glass materials,and still no unified view on the mechanism about the formation of different morphological structure processed with laser-induced materials surfaces.However,study the process of femtosecond laser induced micro-nanostructure evolution of arsenic sulfide glass materials and the ablation mechanism of interaction between femtosecond laser and arsenic sulfide glass have important theoretical significance for laser micromachining on chalcogenide glass.In this paper,we first discussed during nanosecond laser irradiate As2S3 materials,the transient evolution processes of micro-nanostructure on the materials surfaces.And laid the foundation for developing the micro-nanostructure on the material surface during the ablation of As2S3 glass surfaces by femtosecond laser.Then,the femtosecond laser pump-probe device was designed and built,to realize the real-time monitoring of the signal change reflected on the materials surfaces during laser irradiation on materials.In addition,the surface temperature fields of the laser radiating material were simulated by the dual temperature theoretical model.Combined with theory and experiment,the evolution of the surface morphology and thermal properties of the glass surface during the process of femtosecond pulsed laser irradiation of arsenic sulfide were clearly clarified.At different laser energies(8.26 m J/cm2-30.98 m J/cm2),the temperature required to reach the maximum surface temperature range were 6-8 ps.Furthermore,in the low,medium and high laser energy densities,the variations of surface reflection signal intensity required a time range of 43 ps-450 ps during the evolution of the pore structures of the material surfaces.In addition,a high-quality long-period diffraction grating was prepared by adjusting the laser processing parameters,and the first-order diffraction efficiency of the grating was as high as 6.3% at the transmission wavelength of λ=632.8 nm.