Effect of nanoshell geometries, sizes, and quantum emitter parameters on the sensitivity of plasmon-exciton hybrid nanoshells for sensing application.

A proposed nanosensor based on hybrid nanoshells consisting of a core of metal nanoparticles and a coating of molecules is simulated by plasmon-exciton coupling in semi classical approach. We study the interaction of electromagnetic radiation with multilevel atoms in a way that takes into account both the spatial and the temporal dependence of the local fields. Our approach has a wide range of applications, from the description of pulse propagation in two-level media to the elaborate simulation of optoelectronic devices, including sensors. We have numerically solved the corresponding system of coupled Maxwell-Liouville equations using finite difference time domain (FDTD) method for different geometries. Plasmon-exciton hybrid nanoshells with different geometries are designed and simulated, which shows more sensitive to environment refractive index (RI) than nanosensor based on localized surface plasmon. The effects of nanoshell geometries, sizes, and quantum emitter parameters on the sensitivity of nanosensors to changes in the RI of the environment were investigated. It was found that the cone-like nanoshell with a silver core and quantum emitter shell had the highest sensitivity. The tapered shape of the cone like nanoshell leads to a higher density of plasmonic excitations at the tapered end of the nanoshell. Under specific conditions, two sharp, deep LSPR peaks were evident in the scattering data. These distinguishing features are valuable as signatures in nanosensors requiring fast, noninvasive response.

Dragonfly Algorithm and Its Hybrids: A Survey on Performance, Objectives and Applications.

Swarm intelligence is a discipline which makes use of a number of agents for solving optimization problems by producing low cost, fast and robust solutions. The dragonfly algorithm (DA), a recently proposed swarm intelligence algorithm, is inspired by the dynamic and static swarming behaviors of dragonflies, and it has been found to have a higher performance in comparison to other swarm intelligence and evolutionary algorithms in numerous applications. There are only a few surveys about the dragonfly algorithm, and we have found that they are limited in certain aspects. Hence, in this paper, we present a more comprehensive survey about DA, its applications in various domains, and its performance as compared to other swarm intelligence algorithms. We also analyze the hybrids of DA, the methods they employ to enhance the original DA, their performance as compared to the original DA, and their limitations. Moreover, we categorize the hybrids of DA according to the type of problem that they have been applied to, their objectives, and the methods that they utilize.

Proposed new approach to the design of universal logic gates using the electro-optic effect in Mach-Zehnder interferometers.

Efficient application of the electro-optic effect in a lithium-niobate-based Mach-Zehnder interferometer to construct universal gates has been demonstrated. The study is carried out by simulating the proposed device with the beam propagation method, and the results are verified using MATLAB. Various parameters influencing the performance of the device (such as speed, latency, and power consumption) also have been taken into account.

Design of D flip-flop and T flip-flop using Mach-Zehnder interferometers for high-speed communication.

Electrical component speed is a major constraint in high-speed communications. To overcome this constraint, electrical components are now being replaced by optical components. The application of optical switching phenomena has been used to construct the design of the D flip-flop and T flip-flop based on the electro-optic effect in a Mach-Zehnder interferometer (MZI). The MZI structures show the powerful ability to switch the optical signal from one output port to the other. Hence, it is possible to construct some complex optical combinational digital circuits using the electro-optic-effect-based MZI structure as a basic building block. This paper constitutes the mathematical description of the proposed device and thereafter compilation using MATLAB. The study is carried out by simulating the proposed device with the beam propagation method.

Binary encoded computer generated holograms for temporal phase shifting.

The trend towards real-time optical applications predicates the need for real-time interferometry. For real-time interferometric applications, rapid processing of computer generated holograms is crucial as the intractability of rapid phase changes may compromise the input to the system. This paper introduces the design of a set of binary encoded computer generated holograms (CGHs) for real-time five-frame temporal phase shifting interferometry using a binary amplitude spatial light modulator. It is suitable for portable devices with constraints in computational power. The new set of binary encoded CGHs is used for measuring the phase of the generated electric field for a real-time selective launch in multimode fiber. The processing time for the new set of CGHs was reduced by up to 65% relative to the original encoding scheme. The results obtained from the new interferometric technique are in good agreement with the results obtained by phase shifting by means of a piezo-driven flat mirror.

Holographic mode-selective launch for bandwidth enhancement in multimode fiber.

With rapidly growing bandwidth demands in Local Area Networks, it is imperative to support next generation speeds beyond 40 Gbit/s. Various holographic optimization techniques using spatial light modulators have recently been explored for adaptive channel impulse response improvement of MMF links. Most of these experiments are algorithmic-oriented. In this paper, a set of lenses and a spatial light modulator, acting as a binary amplitude filter, played the pivotal role in generating the input modal electric field into a graded-index MMF, rather than algorithms. By using a priori theoretical information to generate the incident modal electric field at the MMF, the bandwidth was increased by up to 3.4 times.