Diagnostic tools such as Point-of-Care (POC) analysis usually requires an on-site testing and measurements. Hence, to ease the fluid sample handling, microfluidics technology has been opted frequently to be incorporated with lab-on-chip (LOC). Therefore, an easy and conventional method of design and fabrication of the microfluidic device implemented. In this study, the device is fabricated with Polydimethylsiloxane (PDMS) and SU-8 using soft lithography technique. Herein, we focus on fluid transportation which is applied in clinical diagnostics and the transfer rate to the desired position as well as the fluid leakage during the transportation. Hence, the microfluidic sample transport channeling provides a practical solution for POC technological advances to study the biological systems that yield a better result in quantitative measurements and providing researchers new tools for life science research. � Penerbit UTHM.

We developed a novel dopamine sensing and measurement technique based on aggregation of gold nanoparticles in random lasers. Dopamine combined with copper ions triggers the aggregation of gold nanoparticles and thus affects the performance of random lasers. Dopamine sensing can be achieved using four parameters which are sensitive to the presence of dopamine, that is emission peak shift, emission linewidth, signal-to-noise ratio (peak emission intensity / noise) and random lasing threshold. The dopamine is most sensitively detected by a change in the emission linewidth with a limit of detection of 1 � 10-7 M, as well as by an increase in the lasing threshold. The dopamine concentration from 1 � 10-7 M to 1 � 10-2M can be determined by calibrating with the laser threshold. �2015 Optical Society of America.

We investigate the effect of different gain media and different scattering media in random lasers. We demonstrate an increase in the emission intensity and efficiency of random lasing by incorporating gold rather than dielectric alumina nanoparticles. There is a trade-off between enhancing the random laser performance due to the localised surface plasmon resonance field effects and reduction in performance due to fluorescence quenching by the gold nanoparticles. We use fluorescence resonant energy transfer between dye molecules to extend the wavelength range of emission. � Copyright 2016 by SCITEPRESS-Science and Technology Publications, Lda. All rights reserved.

We demonstrate the effect of fluorescence resonance energy transfer on the emission spectra and threshold of Rhodamine 6G / methylene blue / titania random lasers. Rhodamine 6G enhances the laser emission of methylene blue at ?700 nm. � 2015 IEEE.

We demonstrate improved characteristics in Rhodamine dye random lasers with the addition of gold nanoparticles. As a result of the strong plasmonic enhancement induced by gold nanoparticles, Rhodamine 640/gold random lasers have less than half the lasing threshold compared with Rhodamine 640/alumina random lasers in the weakly scattering regime for 10-3 M dye concentration. The optimum concentration of gold nanoparticles occurs at ?8 � 1010 cm-3, close to the transition between the weakly scattering and diffusive regimes. Rhodamine 640 has a better performance compared with Rhodamine 6G which is attributed to the greater spectral overlap of the Rhodamine 6G fluorescence spectrum with the plasmon resonance of gold, leading to an increased energy transfer and fluorescence quenching for Rhodamine 6G by gold. We also observe the contrasting trends of lasing threshold between random dye lasers incorporating dielectric and metal nanoparticles in the diffusive scattering regime. The effects of gold nanoparticles in random dye lasers are discussed in the context of the tradeoff between local field enhancement and fluorescence quenching. � 2015 Astro Ltd.

A random laser is an optical device that depends on multiple light scattering and gain to provide the feedback mechanism and light amplification respectively. A random laser is different with a regular laser where the regular laser needs a cavity for the feedback mechanism. Multiple light scattering can be considered detrimental in the regular laser but in the random laser, multiple light scattering can increase the path length of light in the active medium. This article studies the operation principles and characteristics of random lasers including the history and applications of the lasers. The theories of light scattering and light amplification are properly explained, followed by a discussion on characteristics of random lasers in terms of random laser emission, emission linewidth and coherence. Furthermore, the unique characteristics of random lasers can contribute to many applications leading to promising element for the future medical and biosensing development.

A random laser is demonstrated in a hollow-core photonic-crystal optical fibre, with dye solution and dielectric or metallic nanoparticles. The threshold is significantly reduced compared with the bulk solution due to optical guiding and scattering. � OSA 2016.

This article presents the effects of haze attenuation on Radio over Free Space Optic (RoFSO) transmission system in KLIA Sepang, one of the towns in Malaysia. The haze condition which affects the FSO link transmissions was considered on October 2015 and on October 2017 at KLIA Sepang referring to the reading record of Air Pollution Index (API). In this paper, OptiSystem simulation software is used as a preliminary study before configuring the real RoFSO setup. We model the RoFSO by converting the radio frequency (RF) signal into light where the light source intensity is modulated with the RF signal. RF signal travels through free space while light propagates through fiber optic channel. Single-FSO and four- FSO channels are compared and analyzed in terms of bit-error-rate (BER), received optical power and eye diagram pattern. The results show that the performance of RoFSO with four-FSO channel system in comparison with single-channel has better receiver sensitivity and clear eye diagram. For future work, deploying multiple RoFSO system can fulfil the increasing demand for optimizing the communication bandwidth.