In this study, we investigate the third-order nonlinear optical properties of phenol red (PR) solutions and their hybrid composites, analyzing a PR solution with a pH of 7.56, a zwitterionic PR solution (PRz) with a pH of 1.52, and a PR-doped PVA/silica (PR-PS) hybrid composite made using an acid-catalysed sol-gel method and drop-casting technique. The PR-PS thin film exhibits a smooth and homogeneous surface, with a root mean square roughness (RMS) of 0.816 nm and an average roughness, Ra of 0.648 nm. FESEM was employed to analyze the surface morphology and thickness of the thin film, which was found to be approximately 80 µm. UV-vis analysis demonstrates that PR in the matrix is in its zwitterionic form, with absorption peaks at 450 nm and 515 nm. The PVA/silica hybrid matrix exhibits an enhancement in third-order nonlinear susceptibility, χ(3) by 83.94%. Moreover, our finding also indicates that the PR-PS hybrid composite’s β being being 79.09% and 99.37% larger than that of the PR and PRz samples, respectively. These results suggest that the PR-PS thin film is a promising material for photonic applications, such as nonlinear optical switching devices and optical limiting applications, due to its enhanced nonlinear optical properties.

The performances of an electro optic Q-switched Nd:YAG laser at transition line of 4 F3/2→ 4 I11/2 Stark level based on DKDP crystal is presented. The temporal delay time between the ignition of Xenon flashlamp and the Q-switched trigger signal is manipulated to determine the best performances of the Q-switched laser. The results shown that opening the Q-switching is dependent on the pumped energy. The higher the pumping energy the longer the temporal delay is desired to achieve the optimum output. However the temporal delay may remain constant if the laser is pumped with low energy. In general the performance of the Q-switched laser is found independently on the temporal delay, whereby all tested temporal delays almost have similar slope efficiency of 18%.