Nonlinear transmission of fluorophosphate glass with quantum dots of cadmium and lead sulfides and selenides under near-IR of femtosecond laser irradiation

Nonlinear optical properties of fluorophosphate glass with quantum dots of cadmium sulfides and selenides (CdS and CdSe) and lead (PbS and PbSe) were studied using a pulsed femtosecond near-IR laser. Fluorophosphate glasses with CdS, CdSe, PbS and PbSe quantum dots were obtained by high-temperature synthesis with additional heat treatment. Nonlinear absorption was studied under the action of a pulsed laser at a wavelength of 1050 nm and a duration of 100 fs. It is shown that the transmission at 1050 nm in fluorophosphate glasses with CdS and CdSe quantum dots is 0.78 and 0.88, respectively. In addition, increasing the average power of femtosecond laser radiation from 30 to 2000 mW does not lead to a change in their transmission. For this wavelength, the transmission was 0.1 for the sample with PbS nanocrystals and 0.65 for the sample with PbSe quantum dots. A decrease in transmission with increasing laser radiation power was shown for glass samples with PbS and PbSe quantum dots, i. e., nonlinear transmission (limiting) was observed. The threshold for limiting the power of laser radiation passing through the sample, i.e., the power at which the transmission decreases by more than 20 %, for the sample with PbS quantum dots was 1265 mW, and for an input power of about 1530 mW, this sample had a transmission of less than 0.1 %. The laser power limitation threshold for the PbSe quantum dot sample was 600 mW, and for an input power of about 750 mW it had a transmittance of less than 0.1 %. Fluorophosphate glasses with lead sulfide and selenide quantum dots can be used as limiting filters to protect photodetectors from pulsed laser radiation in the near IR range.