1 research outputs found
Third-Order Nonlinear Optical Properties of Aqueous Silver Sulfide Quantum Dots
Wide spectral wavelength
range (500–1600 nm) measurements
of nonlinear optical properties of silver sulfide (Ag2S,
with 2- or 3-mercaptopropionic acid, 2 or 3MPA ligands) quantum dots
(QDs) in aqueous colloidal solutions were performed using the Z-scan
technique with tunable ∼55 fs laser pulses at 1 kHz. We have
identified regions of the occurrence of various NLO effects including
two-photon absorption, nonlinear refraction, as well as saturation
of one-photon absorption. At the same time, we evaluated the relationship
between the properties of the QDs and the variation of the material
that covers their surface. The peak two-photon absorption cross section
(σ2) values were determined to be 632 ± 271
GM (at 850 nm) for Ag2S-2MPA QDs and 772 ± 100 GM
(at 875 nm) for Ag2S-3MPA QDs. The physicochemical factors
influencing the three-dimensional self-organization of Ag2S QDs in water as well as their impact on spectroscopic properties
were also investigated