Abstract
The mechanism of formation of the nonlinear optical response of colloidal solutions of Ag2S quantum dots passivated with thioglycolic acid molecules is considered. Using the Z-scan method for 10 ns pulses of the second harmonic of a YAG:Nd laser, the appearance of nonlinear absorption and nonlinear refraction is shown. A saturating dependence of the absorption coefficient with an increase in the intensity of the incident radiation is found. An assumption was made about the participation in the process of nonlinear absorption of localized states of levels of Ag2S structural defects, including the defect luminescence center, which was confirmed by femtosecond induced absorption spectroscopy. The formation of a broad structureless induced absorption band in the 500–1000 nm region is shown, which decays on a time scale of hundreds of picoseconds. It is concluded that the induced absorption signal is determined by the fast (within fractions of picoseconds) process of charge carrier capture by localized states, which subsequently determine the nonlinear absorption of 10 ns pulses.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
