This paper presents topology optimization for thermal cloaks expressed by level-set functions and explored using the covariance matrix adaptation evolution strategy (CMA-ES). Designed optimal configurations provide superior performances in steady-state conduction succeed realizing invisibility, despite structures being simply composed of iron aluminum without inhomogeneities caused employing metamaterials. To design cloaks, a prescribed objective function is used to evaluate difference...

We generate optimal topologies in the structural design of bifunctional cloaks manipulating heat flux and direct current, using topology optimization that incorporates both thermal conductivity electrical current. The cloak composed bulk isotropic materials is designed to restrain disturbances caused by an insulated obstacle minimizing difference between cloaked distributions referenced when no present. Our results show presented optimizations provide reproduce undisturbed temperature...

This letter presents a level set-based topology optimization method that provides discrete cloaking configurations with superior performance. In some cases, the amount of light scattered around two-dimensional structures is less than one-tenth obtained in previous studies. Optimal express different geometrical characteristics can be by adjusting regularization parameter. The are free from grayscales, areas intermediate density between dielectric materials or air, and use set clear structural...

By including acoustic-elastic interactions in a topology optimization based on the covariance matrix adaptation evolution strategy, we developed acoustic cloaks of optimal design that render an object unobservable through airborne and water-borne sounds. This strategy helps exploring topologies minimize scattering sounds around made from acrylonitrile butadiene styrene copolymers frequently used as ink 3D printers. applying level set methods, our designed are expressed iso-surfaces...

Various strategies have been proposed to achieve invisibility cloaking, but usually only one phenomenon is controlled by each device. Cloaking an object from two different waves, such as electromagnetic and acoustic a challenging problem, if not impossible, be achieved using transformation theory metamaterials, which are the major approaches in physics. Here, developing topology optimization for controlling both we present multidisciplinary attempt designing biphysical cloaks with...

This paper proposes a topology optimization method for dielectric optical cloak that provides results are perfectly free from intermediate materials, based on level set boundary expression and the Finite Element Method. The finite element mesh is re-generated to fit iso-surface of function at every iterative step, remove so obtained optimal structure consists only two material air. First, set-based formulated algorithm proposed exact approach. Next, design requirements device clarified an...

The dependence of the lasing threshold on amount positional disorder in photonic crystal structures is newly studied by means finite element method, not difference time domain method usually used. A two-dimensional model a consisting dielectric cylinders arranged triangular lattice within circular region considered. are assumed to be homogeneous and infinitely long. Positional introduced crystals. Optically active medium interspace among cylinders. population inversion density optically...

The concept of topology-optimized carpet cloaks is presented using level-set boundary expressions. Specifically, these are designed with the idea minimizing value an objective functional, which here defined as integrated intensity difference between electric field reflected by a flat plane and that controlled cloak. Made dielectric material, our to imitate reflections from plane, some cloaks, functional falls below $0.12%$ for bare bump on plane. These optimal spontaneously satisfy...

Recent remarkable developments in metamaterials and metadevices manipulating diffusive processes, such as thermal electrical conduction, have enabled the control of multiple phenomena development multifunctional devices. However, only either multiphysics operations or functionalities are usually implemented on single metadevices. In this paper, we describe a method for optimal design that achieves both cloaking focusing heat flux direct current by device, i.e., biphysical-bifunctional having...

Based on the covariance matrix adaptation evolution strategy (CMA-ES), advanced designs of direct-current (DC) electric cloaks composed bulk isotropic materials are presented through a topology optimization using level set method. The designed DC succeed in providing invisibility an electrical insulator flow; specifically, potential distribution is found that closely reproduces when no present. To produce this invisibility, we minimized difference between distributions for cloak and one...

We succeeded in simultaneously cloaking and concentrating direct current a conducting material through topology optimization based on level-set method. To design structures that perform these functions simultaneously, optimal is explored for improving two objective govern separately the concentration of current. Our scheme, i.e., direct-current electric cloak concentrator, provides this bifunctionality well despite simple, common bulk materials being used to make up structures. The also...

Mechanical cloaks made from elastic metamaterials that make objects unfeelable have been developed, but usually each cloaking device performs only a single function. In this Letter, we present our computational attempts at instilling two different functionalities, and stress concentration, in metastructure designed through topology optimizing mechanical cloak-concentrator for linear elasticity. Solving optimization problem involved improving objective functions, one the other concentration....

Optimal designs of direct current (DC) carpet cloaks are obtained using topology optimization based on the covariance matrix adaptation evolution strategy. The cloaking structures expressed an immersed boundary-level set method visualized as gray-scale-free configurations and composed simply homogeneous materials. These successfully hide bumps made electrically invisible through by minimizing difference in voltage distributions around cloaked bump over flat surface absence bump. Moreover,...

Topology-optimized designs of multiple-disk resonators are presented using level-set expression that incorporates surface effects. Effects from total internal reflection at the surfaces dielectric disks precisely simulated by modeling clearly defined boundaries during topology optimization. The electric field intensity in optimal increases to more than four and a half times initial resonant state, whereas some cases Q factor three for state. Wavelength-scale link structures between...

We investigated several types of random lasing modes against frequency and the excitation active medium. Random occurring from multiple light scatterings interference effect scattered has various complex states in disordered structures, which waves are localized forms. Modes generally classified into localized, extended transition based on their localization types. Numerical methods used for analysing such phenomena. In this paper, a finite-element method is to investigate relationship among...

It has been observationally confirmed that the color of birds, such as kingfisher and red-flanked bluetail, is a structural owing to interference light within sponge structure inside barb. In this study, we consider air rod photonic crystal which disorder introduced into translation vectors radius model bluetail; optical property numerically analyzed compared with color.