Label free identification of the different status of anemia disease using optimized double-slot cascaded microring resonator.

An optical-based label-free biosensors including two indirectly coupled double-slot-waveguide-based microring resonator was designed and optimized for sensing purpose. Then, the optimized system was applied for the detection of hemoglobin concentration in anemia disease. The results were simulated based on the variational finite-difference time domain (varFDTD) method using the Lumerical software (Mode solutions) and the optimum geometrical parameters were determined to realize an optimum light transmission via the sensor. Nine different concentrations of hemoglobin in men and women were applied into the sensor and the status of anemia was identified based on the patients' gender and different status of anemia disease, including the normal, mild, moderate, severe and life-threatening status. A sensitivity as high as 1024 nm/RIU with the minimum deflection limit of 4.88 × 10-6 RIU were measured for this biosensor, which introduces a high precision and micro-scale lab-on-a-chip micro device for health monitoring of the anemia.

Analytical microring stereo system using coupled mode theory and application.

A stereo resonating system, including two cascaded Panda resonators with two small rings is proposed as a microscale active stereo system. The optical transfer functions of the Panda stereo system for two input ports and one output port are derived using the coupled mode theory. The feasibility of the Panda stereo system to realize three-dimensional content is investigated by applying different coupling coefficients and materials to each Panda resonator. The effect of the coupling strength of the ${3} \times {3}$3×3 coupler on the output light is also studied. It is interesting that a portion of input light into the Panda stereo system can undergo a wavelength shift and an intensity shift by adjusting the coupling coefficients of the ${3} \times {3}$3×3 coupler together with fine-tuning the refractive index of one of the Panda resonators. Results show that a change of the ${3} \times {3}$3×3 coupler brings about a shift from 0.1 to 37 dB in light transmission and applying a change of $\delta n = 0.01$δn=0.01 in the refractive index of one of the Panda resonators generated a phase shift larger than $\pi /{4}$π/4, which is required for image depth reconstruction. The advantages of the proposed Panda stereo system compared to the conventional stereo technology are low cost and a microsize, with a simple structure and the ability to work in a different wavelength spectrum range.

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 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.

Sensing and identification of carbon monoxide using carbon films fabricated by methane arc discharge decomposition technique.

Carbonaceous materials have recently received attention in electronic applications and measurement systems. In this work, we demonstrate the electrical behavior of carbon films fabricated by methane arc discharge decomposition technique. The current-voltage (I-V) characteristics of carbon films are investigated in the presence and absence of gas. The experiment reveals that the current passing through the carbon films increases when the concentration of CO2 gas is increased from 200 to 800 ppm. This phenomenon which is a result of conductance changes can be employed in sensing applications such as gas sensors.

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 signal's 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 port's 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.

Ultrafast all-optical switching using signal flow graph for PANDA resonator.

In this paper, the bifurcation behavior of light in the PANDA ring resonator is investigated using the signal flow graph (SFG) method, where the optical transfer function for the through and drop ports of the PANDA Vernier system are derived. The optical nonlinear phenomena, such as bistability, Ikeda instability, and dynamics of light in the silicon-on-insulator (SOI) PANDA ring resonator with four couplers are studied. The transmission curves for bistability and instability as a function of the resonant mode numbers and coupling coefficients for the coupler are derived by the SFG method and simulated. The proposed system has an advantage as no optical pumping component is required. Simulated results show that closed-loop bistable switching can be generated and achieved by varying mode resonant numbers in the SOI-PANDA Vernier resonator, where a smooth and closed-loop bistable switching with low relative output/input power can be obtained and realized. The minimum through-port switching time of 1.1 ps for resonant mode numbers of 5;4;4 and minimum drop port switching time of 1.96 ps for resonant mode numbers of 9;7;7 of the PANDA Vernier resonator are achieved, which makes the PANDA Vernier resonator an operative component for optical applications, such as optical signal processing and a fast switching key in photonics integrated circuits.