OPTICAL AND NONLINEAR OPTICAL PROPERTIES GLASSES OF THE GeS2-As2S3-Er2S3 SYSTEM

Abstract

Chalcogenide glasses doped with rare earth ions have attracted considerable attention of researchers due to their widespread use in optoelectronics, in particular in lasers operating in the mid-infrared range. At the same time, it is possible to change the parameters of such lasers by changing the chemical composition of the source material. One of the most promising impurities in chalcogenide glasses is Erbium, which is due to its ability to efficiently emit quanta of electromagnetic waves at the standard telecommunication wavelength of 1540 nm. It is practically impossible to predict the properties of glasses using only the theory of the processes of absorption and emission of light, so the study of the effect of Er3+ impurities on the optical properties of chalcogenide glasses lies in the experimental plane. The scope of applications of the studied materials in optoelectronics is related to the width of the band gap. To estimate the optical band gap, a study of the spectral distribution of the absorption coefficient in the region of the edge of the intrinsic absorption band was conducted. The width of the forbidden optical band gap is estimated. It was established that as the molar fraction of As2S3 in the studied glasses of the GeS2 – As2S3 – Er2S3 system increases, the absorption edge shifts to the longwavelength region, which reflects the reduction of the optical band gap. The decrease in the band gap with an increase in the molar fraction of As2S3 is due to the fact that As2S3 has a smaller band gap than glassy germanium disulfide. The study of the generation of the second and third harmonics was conducted. The achieved parameters of nonlinear optical effects of the third order make it possible to predict the wide application of the studied glasses as materials for nonlinear optical conversion of IR laser beams, which is of crucial importance for IR lidar systems (light rangefinders). The coexistence of the photoinduced generation of the second harmonic and the generation of the third harmonic (obtained without laser stimulation) opens up the possibility of using the studied glasses in optoelectronic devices that operate simultaneously on doubled and tripled frequency signals.