الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 128 |  |  |
| | | from | 128 | | |
Abstract
The study of how light behaves in nonlinear media is the focus of the important and expanding discipline of physics known as nonlinear optics (NLO). NLO is beneficial in a variety of fields, including telecommunications, astronomy, laser technology, photonic devices, quantum computing, and many more. For many years, researchers have been collaborating in the NLO sector to create fresh viewpoints and approaches for changing the environment that we live in. The concepts in this subject have led to tests, and those experiments have produced an extremely intriguing application.
This research dissertation entitled “Ultra-short Laser Pulses to study the Nonlinear Optical of Gold Nanoparticles Synthesized by Laser Ablation” concerns of an experimental study of the linear and nonlinear optical properties Gold Nanoparticles. We investigated the nonlinear optical properties of Au nanoparticles (AuNPs) produced by laser ablation in pure distilled water using the Z-scan experimental method. A nanosecond Nd:YAG laser with an ablation time of 5 or 10 minutes and a constant laser intensity of 100 mJ was used to create the AuNPs.
An investigation of the UV-visible spectrophotometer and a transmission electron microscope (TEM) were used to investigate the structure and linear optical characteristics of the Au NPs. According to the TEM studies, the average Au NP size varied depending on the laser ablation period from 20.3 to 14.1 nm.
The nonlinear refractive index (n2) and nonlinear absorption coefficient (γ) of the Au NPs, which were irradiated at various excitation wavelengths ranging from 740 to 820 nm and at various average powers ranging from 0.8 to 1.6 W, were investigated using the z-scan technique. The reverse saturable absorption (RSA) behaviour of the Au NP samples showed an increase with the excitation wavelength and/or incident laser intensity. In furthermore, whether the excitation wavelength or incident power were changed, the Au NPs functioned as a self-defocusing material.