Tamer A. Ali

In this study, we propose a new design based on photonic crystal fibers (PCFs) for broadband dispersion compensation in telecommunication networks. The proposed design has a hexagonal structure arrangement of air-holes rings of different diameters between the silica core and the cladding. The PCF properties like effective area, nonlinearity, dispersion slope, confinement loss, and birefringence are reported and discussed. For the best performance we present three designs A, B and C. Simulation results show that the three designs cover the six-telecommunication optical bands O-, E-, S-, C-, L- and U- bands (wavelengths ranging from 1260 to 1675 nm). Design A achieves a large negative dispersion value of about − 1716 ps/(nm.km) with relative dispersion slope equals to that of conventional single-mode optical fibers (SMFs) of about 0.0036 nm⁻¹, which makes it very suitable for long-haul DWDM transmission systems. With a little modification in the core, designs B and C achieve much higher confinement ability and achieve a very large birefringence value for polarization mode dispersion and sensing applications. Design C is engineered to have exact opposite dispersion of SMF with zero dispersion at the wavelength 1310 nm, which makes it a promising design in CWDM transmission system. The numerical values have been investigated using the full vector finite element method.

Modeling of nano-structured plasmonic surfaces in optical range has attracted great attention in recent research for its various optical properties such as filtering and enhanced transmission of light. In this paper, we present a simple nanocircuit model that can be integrated in CAD tools to design filters and perfect absorbers FSS devices that are based on plasmonic transmission through thin films structured by hole arrays. To illustrate the model potential, we applied it for both circular and square hole arrays on a silver thin film. The model is demonstrated for different structure parameters (hole size and film thickness) in optical frequencies. We show that the model results compare to the numerical calculations obtained from COMSOL Multiphysics software with acceptable deviation and that the model achieves good matching with previously reported experimental measurements.

The accessibility of a rapid method for detection and identification of food‐borne pathogens is crucial for food industry worldwide. Antibiotic resistance bacteria (eg, E. coli) that can enter the food chain in different ways, can indeed survive on foods causing disease to humans. Hence, the introduction of a rapid detection technology becomes necessary for the food industry to ensure consumer safety, especially for products with short shelf lives. Bacteriophages can be used to detect and identify bacteria. In this study, a novel biosensor is proposed to detect pathogens by means of phage‐based baroreceptor. The biosensing technique is based on millimeter‐waves technology in the 30 to 60 GHz frequency range. The proposed biosensor can detect the pathogenic bacteria in different food samples by using a diamond‐shape microstrip slot antenna. The bacteriophage‐bacterium interaction is detected through the dynamic changes in transmission lines and antennas responses. The correctness of the antenna to detect E. coli in real food sample (tomato) is also investigated. The results indicate that, through the designed sensing elements, the transient interaction between bacteria and phage can effectively be detected. This sensing mechanism allows for a faster, more accurate, and low‐cost detection of pathogenic bacteria than traditional assays. Finally, the results are compared with previously reported sensing techniques.

The authors theoretically propose a design for electrically tuning a metasurface based on piezoelectric actuation. The design comprises 2D gap‐plasmon elements arranged periodically on a piezoelectric substrate which controls the period between them. The technique is numerically studied for a metasurface that anomalously reflects an incident p‐polarised wave by 30° at the optical communication wavelength, 1550 nm. The dynamic behaviour of the system is investigated for two main applications; (a) steering the reflection angle and (b) retrieving the reflection angle for an incident wave of a shifted wavelength. It is demonstrated that a reflected beam can cover an angle of ∼3° upon a strain of <3.3%. It is also shown that at the same strain value, the reflection angle is retrieved for a wavelength error of ±50 nm. These results suggest a potential to design large‐bandwidth, reconfigurable metasurfaces that are integrable with planar opto‐electromechanical devices.