جستجوی مقالات مرتبط با کلیدواژه "photonic crystal" در نشریات گروه "علوم"

During the process of evolution, nature has encountered a multitude of challenges, which have been met with the development of optimal solutions through the mechanism of natural selection. These solutions have undergone refinement over time, resulting in the creation of highly efficient and enduring strategies. One particular challenge that nature has faced is the phenomenon of color change in organisms. A significant mechanism for generating color involves the utilization of one- to three-dimensional photonic crystal structures, which give rise to bright and rainbow colors. These structures have been observed in a variety of organisms, including insects (such as cockroaches and butterflies), birds (such as peacock feathers), plants (such as Edelweiss flowers), and marine animals (such as fishes and sea worms). The phenomenon of color change facilitated by these structures serves a range of purposes, such as sexual communication, cryptic behavior, adaptation to the environment, and the deterrence or deception of predators. In this review, we address the photonic crystal structure-mediated color change in fish, beetles, and butterflies. Finally, we explore various industries bioinspired of these structures, including artificial colors, sensors, solar cells, nanolithography, display screens, and banknote counterfeiting.

In this paper، the Mutiple Multipoles method is employed to solve nonlinear eigenvalue problem and calculate band structure for a 2D photonic crystal. Band structure is calculated for both TE and TM polarizations. Simulation space is implemented for the first Brillouin zone by using physical properties such as rods radius، permittivity and susceptibility. To model fields inside and outside of object، Multipole centers were located around it and Bessel series inside the object is shown complex fields. We used Bloch theory to implement fictitious periodic boundary conditions for the first Brillouin zone. To validate the code، we simulated the band structure of a cubic lattice and compare the results with Plane Wave Expansion Method which illustrates the accuracy of the code. It is shown that this method can be applied to investigate photonic crystals with irregular shapes and different materials for different lattices such as cubic، trigonal and honeycomb. Furthermore it could be used for dielectric or dispersive material and experimental data. Numerical calculation shows that MMP method is accurate، fast and it can be used on Personal Computers.