Ahmad Fakhrurrazi Ahmad Noorden

Modeling and Analysis of a Microresonating Biosensor for Detection of Salmonella Bacteria in Human Blood

A new photonics biosensor configuration comprising a Double-side Ring Add-drop Filter microring resonator (DR-ADF) made from SiO2-TiO2 material is proposed for the detection of Salmonella bacteria (SB) in blood. The scattering matrix method using inductive calculation is used to determine the output signals intensities in the blood with and without presence of Salmonella. The change in refractive index due to the reaction of Salmonella bacteria with its applied antibody on the flagellin layer loaded on the sensing and detecting microresonator causes the increase in through and dropper ports intensities of the output signal which leads to the detection of SB in blood. A shift in the output signal wavelength is observed with resolution of 0.01 nm. The change in intensity and shift in wavelength is analyzed with respect to the change in the refractive index which contributes toward achieving an ultra-high sensitivity of 95,500 nm/RIU which is almost two orders higher than that of reported from single ring sensors and the limit of detection is in the order of 1 × 10−8 RIU. In applications, such a system can be employed for a high sensitive and fast detection of bacteria.

Detection of Salmonella bacterium in drinking water using microring resonator

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 ports 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− 4RIU.

Circuit analysis on the inductance evolution based on electrical signal from various type plasma focus device

Numerous configurations of plasma focus devices (PFD) have been introduced around the globe. The distinct electrode configuration of the PFD will give out different inductance profile. A circuit analysis has been done to study on the significant difference between the inductance evolution in a coaxial discharge based on various published results of PFD. The discharge current signal, tube voltage and current derivative of the particular shots from distinct PFD was digitized and analyze. The investigation was piloted for three different types of PFD. It was observed that there is a significant difference for the normalize inductance profile during the discharge between the individual PFD with different electrode configuration. The depletion of the radial start current with the normalised inductance development for Mather type (PF-1000) is found to be 25.9% from static discharge. The current depletion continues to drop 1.1% and 1.3% more for a Spherical type (PNK-13) and Filippov type (PF-3) respectively.

Implication of plasma dispersion effect for controlling refractive index in microresonator

In this paper, the theoretical simulation of all-pass microring resonator is performed by considering the plasma dispersion effect. The plasma dispersion contributes in changing the refractive index and resonance wavelength by manipulating the carrier concentration in silicon waveguide. The system requires a sandwich design of silicon microring waveguide which comprise P and N-types silicon material. The depletion region is bounded in the ring resonator waveguide which affect the carrier concentration of the silicon material. The plasma dispersion effect formulation contributes to analyze the effect for applied voltage on effective index and absorption coefficient. The shift of resonance wavelength is analyzed with respect to the change of refractive index.

Arc discharge plasma of carbon ion in H2 and air

Carbon nanostructures become more useful nowadays due to their unique carbon elements and advantages. This paper will present the determination of the energy of carbon ion in different environments and pressures. In this work, arc discharge plasma generated by graphite electrode were chosen to produce carbon nanostructures and CR-39 material were exposed to energetic carbon ion. It was etched with 6.25 M of NaOH solution for 8 hours in (72±1) °C temperature to remove the material from the tracks and the etched detectors will be analyzed with optical microscope. The energy of carbon ion obtained by observing and measured the ion track size on CR-39 target under optical microscope and calculated using the relevant formula. High values of carbon ions energy were observed in hydrogen environment as compared to air at the same pressure.