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.

Potential of hybrid gold nanoparticles/graphene oxide (AuNPs/GO) coated single mode fiber (SMF) sensor by exploiting localized surface plasmon resonance (LSPR) effect for Musta’mal water identification was studied. Three structure shapes of fiber optics such as straightshape, loop-shape and u-shape had been prepared. Three layers of AuNPs with 50 nm in diameter were drop-casted onto the partially unclad polished single mode fiber (SMF) to observe the maximum sensitivity of LSPR. To enhance the LSPR effect, one layer of GO was deposited on top of the AuNPs layer. Two optical light sources with least attenuation (1310 nm and 1550 nm) were employed to study the optical power output as the sensor immersed in different type of water samples. The u-shape SMF portrayed the maximum output power about 24.2 dBm at 1550 nm wavelength. According to the analysis, the deployment of 1550 nm laser wavelength resulted in better sensitivity with 23.2% improvement compared to 1310 nm wavelength. Apparently, the LSPR phenomenon created by AuNPs/GO able to enhance the plasmonic signal up to 51.9% than the uncoated SMF. The thinnest diameter of SMF’s cladding, d=0.1195 mm with U-shape structure exhibited the highest power different of 1.10 dBm, in which suggested the best sensing performance. In conclusion, the optimization of AuNPs/GO u-shape polished SMF resulted in the maximum sensitivity with value of S=72.7 dBm/RIU for Musta'mal water identification.

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%.

Passively Q-switched Nd:YAG laser pumped by flashlamp is demonstrated by using a saturable absorber made of a multi-walled carbon nanotubes-polyethylene oxide (MWCNTs-PEO) film. Two positions of the film are tested in the resonator to optimize its performance. The maximum pulsed energy obtained for the Q-switching operation is 1.68 mJ corresponding to 88.36 J electrical pump energy. The pulse duration of 83.64 ns is achieved with a peak power of 20.1 kW. A MWCNTs-PEO-film is a promising saturable absorber because of its simple cavity design, reliable and low cost fabrication compared to normal nonlinear crystal absorber.

A simple and low-cost Fiber Optic Displacement Sensor (FODS) using reflective intensity modulation technique was developed to analyze various concentrations of Pb2+, a compound classified under heavy metal ions. Lead is harmful to the environment including to human but is used in the cosmetic field for beauty without realizing and considering the hazardousness of lead as it would cause a long-term effect. Therefore, a feasible way has been identified in this study to demonstrate the level of Pb2+ concentration in cosmetics field by employing the theory of modulation of intensity as a function of displacement sensor. The permissible limit according to Malaysian Cosmetics Guidelines and ASEAN Cosmetic Directive was 20 ppm. The concentration sensor’s system exhibits 0.0018 V/ppm sensitivity with a linearity of 96% and 94% respectively, for both peaks. Meanwhile, the sensitivity was 0.034 V/ppm for the first peak and 27.72 V/ppm for the second peak, with slope linearity of more than 96% for surface tension parameter. The credibility of these optical response curves data might be useful, especially in the cosmetic’s industrial application.

The creation of technology in this century changes people’s life. Technology plays an important role that benefits young people and has increased agriculture production’s efficiency and profitability. Innovative technology mainly involved in animal feeding automation is currently one of Smart Bran Dispensers’ new inventions. This project approaches an innovative animal husbandry management system to improve the agricultural system’s efficiency, particularly livestock nutrition and feed resources. The benefit of this project is to facilitate animal feeding for breeders, which can be remotely controlled and detected by a tracking module that transmits a signal to the user and informs them of the status of the bran dispenser through the Blynk server. NodeMCU ESP8266 and Arduino UNO were implemented as the main controller.

In conventional lithium-ion batteries (LIBs), carbon compounds are commonly utilised as the anode owing to their great performance, low cost, and abundance. However, due to the limited storage capability of pure carbon materials that restrict further improvement of LIBs, zinc oxide (ZnO) has been one of the promising anode materials to be used as an alternative to strengthen the electrochemical performance of LIBs due to its high theoretical capacity of 987 mAh g-1. This study aims to synthesise ZnO:Al nanowires using the hot-tube thermal evaporation method. Three types of samples are made using this method by varying the concentration of 0 wt% (S1), 3wt% (S2), and 6 wt% (S3) of aluminium (Al) during the Al deposition process. The EDX findings indicated that the sample has a high proportion of zinc (Zn) and oxygen (O), with the S3 sample having the highest Al concentration after being deposited. The most substantial diffraction peak for XRD of all samples was found at (101), exhibiting a single crystalline hexagonal structure with optimum growth direction on the c-axis. For EIS analysis, the S3 sample has the lowest bulk resistance and maximum ionic conductivity. In conclusion, the ZnO sample with 3 wt% of Al as a dopant was selected as the optimum result to synthesise a homogenous surface of ZnO:Al with good crystallinity by using a hot-tube thermal evaporation process and giving the best conductivity in electrochemical performance.  

A nanostructured zinc oxide (ZnO) with different percentages of argon and oxygen gas flow rate was deposited on a silicon wafer by a simple hot tube thermal evaporation technique. The effect of different percentages of gas flow rate on the crystal structure, surface morphology and optical properties were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and RAMAN spectroscopy, respectively. The changes of morphologies from FESEM were significant where the grown ZnO nanostructures show three different shapes which are nanotripods, nanoclusters and nanorods at 5%, 10% and 25% of oxygen gas, respectively. EDX results revealed that Zn and O elements have a major percentage in the sample indicating a composition has high purity of ZnO. XRD patterns displayed the most intense diffraction peak of ZnO at (101), which exhibited a single crystalline hexagonal structure with preferred growth orientation in the c-axis. RAMAN scattering study found that synthesized ZnO shows the high intensity of E2 mode and low intensity of E1 mode attributed to all the samples having good crystal quality containing fewer structural defects. In conclusion, the E15 sample with a 25% oxygen gas flow rate was selected as an optimum result for synthesizing a homogenous surface and high crystallinity of ZnO by using a hot tube thermal evaporation process. This work can enhance the development of ZnO production in various applications.