The synthesis of graphene and graphene quantum dots (GQDs) employing various approaches with a range of precursors, chemicals, and parameters has been reported. Most of the top-down and bottom-up techniques employ strong and hazardous chemical environments, complicated and tedious procedures, are time-consuming, and often require special equipment. Another drawback of the techniques reported is the production of agglomerated, inhomogeneous, and non-dispersible graphene in aqueous solvents or organic solvents, thus limiting its application. This work specifically and comprehensively describes the electrochemical exfoliation of graphene and GQDs, which is often considered as a simple one-step, facile, non-hazardous, and highly efficient technique yet favourable for mass production. A brief discussion on the advantageous and challenges of the electrochemical technique and applications of the electrochemically exfoliated graphene and GQDs is also presented.

A new microring resonator system is proposed for the detection of the Salmonella bacterium in drinking water, which is made up of SiO2-TiO2 waveguide embedded inside thin film layer of the flagellin. The change in refractive index due to the binding of the Salmonella bacterium with flagellin layer causes a shift in the output signal wavelength and the variation in through and drop port's intensities, which leads to the detection of Salmonella bacterium in drinking water. The sensitivity of proposed sensor for detecting of Salmonella bacterium in water solution is 149 nm/RIU and the limit of detection is 7 × 10(-4)RIU.

In this paper, a microring resonator (MRR) system using double-series ring resonators is proposed to generate and investigate the Rabi oscillations. The system is made up of silicon-on-insulator and attached to bus waveguide which is used as propagation and oscillation medium. The scattering matrix method is employed to determine the output signal intensity which acts as the input source between two-level Rabi oscillation states, where the increase of Rabi oscillation frequency with time is obtained at the resonant state. The population probability of the excited state is higher and unstable at the optical resonant state due to the nonlinear spontaneous emission process. The enhanced spontaneous emission can be managed by the atom (photon) excitation, which can be useful for atomic related sensors and single-photon source applications.Optical microring resonator (MRR) has emerged as a potential photonic structure in integrated technology with low power consumption [1] . MRR contributes in various technological applications, such as optical sensors [2] , optical amplification [3] , polarization conversion [4] , optofluidic devices [5] , optical spin generators [6] , frequency shifters [7] and on-chip spectrometry bio-analysis [8] . In quantum, the interaction between atoms and electromagnetic field is described precisely by the energy state transition as interaction phenomenon occurs in small distance with short time.The probability of atom transition between two energy levels is used to explain the interaction between electromagnetic field and atoms. Based on the perturbation theory, the atomic state population remains constant, as the probability amplitude of an atom transiting to other energy states is small. However, in presence of strong light field, the atomic population increases in higher energy level [9] . The probability of atom transition is found in form of oscillation against time which shows that the atom could be in ground or higher energy level, and such oscillations are known as Rabi oscillation [10] . The energy states for a system can be analyzed using the Hamiltonian of time-dependent Schrodinger equation for the light-atom interaction.In this paper, a theoretical formulation for the optical bright soliton pulse propagation within the nonlinear silicon-on-insulator (SOI) double-series microring resonator (DSMRR) system is presented based on optical transfer function [11] and scattering matrix method [12] . The SOI shows the nonlinear optical properties at various wavelengths, which provides strong light confinement [13] and is suitable for high-speed passive-waveguide applications. The Rabi oscillation at the through port of DSMRR system is described by the Hamiltonian, which represents the atoms with ambient surrounding as an unperturbed condition and the atoms interacting with optical bright soliton beam as a perturbed condition. The Rabi frequency equations for the interaction between atom and light within the DSMRR system are obtained by the analytical derivation of two-level atom approxima...

A double series configuration of a microresonator is proposed to measure the amount of corrosion on iron metal. A numerical computation has been performed for analyzing the sensing operation in which the metal is attached to the waveguide as a top cladding material. The transparency peak profile and transfer function of the output transmission spectrum is obtained using a signal flow graph method and Mason's rule. The output spectrum of the microresonator shows that the linear free spectral range (FSR) changes as the iron begins to oxidize, which affects the cladding index of the sensing system. The FSR changes with respect to the amount of corrosion present in iron metal. In addition, the microresonator is able to distinguish two different types of corrosion, which are hematite and magnetite. The ▻ Authors ▻ Keywords Brought to you by INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA Search Sources Lists ↗ SciVal Create account Sign in References (39) Author keywords all-optical corrosion sensor double-series microresonator refractive index Indexed keywords Engineering controlled terms: Cladding (coating) Hematite Iron Magnetite Metal analysis Refractive index Resonators Signal flow graphs Engineering uncontrolled terms All optical Corrosion sensor Double series Free spectral range Micro resonators Numerical computations Output transmission Types of corrosions Engineering main heading: Corrosion Funding details

Morphology effect is one of the essential factors that influence the performance of electrochemical biosensors based on ZnO nanostructures. These nanostructures are characterized by anisotropic growth with different dimensionalities such as zero-dimensional, one-dimensional, and two-dimensional. More interestingly, when combining each dimension into another advanced dimensionality, i.e. the three-dimensional (3-D), exceptional properties can be generated that are not otherwise found in low dimensionalities. The outstanding popularity of 3-D ZnO stems from many factors, with one of the most important being its synergic advantages from its low dimensional sub-unit and the additional surface area of the 3-D structure due to an increased geometric volume. This review briefly describes the principles and growth mechanism factors of 3-D ZnO via solution-based approaches and additional advanced methods. The paper further expands on the latest advancement of research into the 3-D ZnO nanostructure-based electrochemical biosensors to detect biomolecules that harm humankind. We also discussed the analytical performance of these biosensors using different nanocomposite materials. Additionally, limitations and suggestions on particular sensing works are proposed. Lastly, the five-year progress in research into 3-D ZnO-based electrochemical biosensors’ performance in healthcare diagnosis is compared and future challenges presented.