Hoda Aleali

TL;DR: In this paper, nonlinear refraction properties of 3-nm sized silver sulfide (Ag 2 S) semiconductor nanocrystals dispersed in the dimethyl sulfoxide with varying concentrations are reported.

Abstract: Stabilized gold nanoparticle (AuNP) colloids have been fabricated by nanosecond pulsed laser ablation of a pure gold plate in cyclohexanone. The AuNPs colloid exhibits a UV-Vis absorption spectrum with a surface plasmon absorption peak at about 540 nm. Scanning electron microscopy has shown the formation of spherical AuNPs with average size about 53 nm. The shift of 24 cm -1 is observed in the carbonyl band of the colloid using FTIR spectroscopy. This shift indicates that the monomer carbonyl group of cyclohexanone interacts with the surface of the AuNPs and leads to stabilizing the colloid. A large nonlinear refractive index of -2.92 x 10 -7 cm 2 /W is measured using the Z-scan technique under continuous wave laser irradiation at 532 nm. Our results show that the large induced nonlinear refraction is attributed to the surface plasmon resonance (SPR) enhancement effect of AuNPs, high thermo-optic coefficient and low thermal conductivity of cyclohexanone. Observation of far-field diffraction ring patterns confirm a thermally induced negative lens effect and spatial self-phase modulation in the laser beam as it traverses the colloids.

TL;DR: In this paper, the authors investigated the optical limiting performance of an Ag 2 S NP colloid under exposure to nanosecond pulsed laser irradiation at 532 nm and found that nonlinear scattering plays an important role in the limiting action of the sample.

TL;DR: In this paper, the authors reported the magnitude and the sign of optical nonlinearities of silver sulphide nanoparticles (Ag 2 S NPs) dispersed in the DMSO under exposure to 532nm, 15 nanosecond (ns) pulsed laser irradiation.

TL;DR: In this article, the effect of the gold nanoparticle concentration on thermo-optical properties of colloidal gold nanoparticles was investigated using the Z-scan technique, which revealed that the heat diffusion in the colloids is due to nonlocal thermal process.