Using femtosecond laser pulses to explore the nonlinear optical properties of Au NP colloids that were synthesized by laser ablation
Document Type
Article
Publication Date
9-1-2022
Abstract
In this study, we experimentally investigated the nonlinear optical properties of Au nanoparticles (Au NPs) that were prepared in pure distilled water using the laser ablation method. The Au NPs were prepared using a nanosecond Nd:YAG laser with an ablation time of 5 or 10 min at a constant laser energy of 100 mJ. The structure and the linear optical properties of the Au NPs were investigated using a transmission electron microscope (TEM) and UV-visible spectrophotometer analysis, respectively. The TEM measurements showed that the average size of the Au NPs varied from 20.3 to 14.1 nm, depending on the laser ablation time. The z-scan technique was used to investigate the nonlinear refractive index (n(2)) and nonlinear absorption coefficient (gamma) of the Au NPs, which were irradiated at different excitation wavelengths that ranged from 740 to 820 nm and at different average powers that ranged from 0.8 to 1.6 W. The Au NP samples exhibited a reverse saturable absorption (RSA) behavior that increased when the excitation wavelength and/or incident laser power increased. In addition, the Au NPs acted as a self-defocusing material whenever the excitation wavelength or incident power were modified.
Keywords
Nonlinear optics, Nanoparticles, Femtosecond laser, High repetition rate, Gold nanoparticles, Nonlinear absorption, Nonlinear refraction
Divisions
Science
Funders
Science and Technology Development Fund (STDF) [30147]
Publication Title
Nanomaterials
Volume
12
Issue
17
Publisher
MDPI
Publisher Location
ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND