Optical Devices With Metamaterials

In recent years, metamaterials with special electromagnetic properties have attracted much attention. In order to manipulate the propagation of electromagnetic wave, many researchers have designed a diverse range of metamaterial structures with, some potential applications in physics, communication, medicine, military and other fields. This thesis focuses on designing perfect rotator, inside-out Eaton lens and DB boundary by using metamaterials, as follows. 1. Designing perfect field rotator in microwave, THz frequency and nearinfrared band.We start from analyzing the anisotropic unit cells made of perfect metal plate embedded in the air, and the effective permittivity tensor of such unit cell could be obtained by the numerical simulations. After that we demonstrate that a fanlike shape composed of these unit cells could perform the field rotation effect, but with a little scattering. To overcome scattering, by changing the dielectric permittivity of background and the inner core of the device as a value of 1.4, we can realize the perfect field rotator, which works in a broadband of frequencies in microwave. In addition, we expand the working frequency of the perfect rotator to THz frequency range and near-infrared band. To realize the field rotator in such frequencies, we propose a waveguide model composed of air, silicon. and 2Si O. Finally, the two perfect field rotators are presented by means of drilling in the silicon region so that the devices work in the THz frequency and near-infrared band. And the nearly perfect field rotators are displayed from the numerical simulations. 2. The performance of inside-out Eaton lens made of H-fractal metamaterialWe briefly describe the optical properties of three lens, i.e., Maxwell fish-eye lens, Luneburg lens and Eaton lens, and we mainly focus on the imaging functionality of inside-out Eaton lens, which demonstrates that both objects and images locate in the vacuum core. To achieve the effective refractive indexes of such lens, we design and fabricate a sample composed of H-fractal patterns of copper printing on a printed circuited broad. Finally, by measuring the field distribution of such device in microwave, we observe good imaging effect, which verifies the imaging functionality of inside-out Eaton lens in the experiment. 3. The implementation of artificial DB boundary using SRR and ELC resonatorWe analyze and compare the reflection properties of three different kinds of electromagnetic boundaries, including perfect electric conductor, perfect magnetic conductor and DB boundary. It is shown that the DB surface not only completely reflects wave but also keeps the incident polarization and the phase information. For a right-handed or left-handed circularly polarized wave incident onto this boundary, the reflected wave retains its handness. Then we design and fabricate the DB boundary materials made of a metamaterial group consisting of magnetic resonator SRR and electric resonator ELC unit in the microwave range. The corresponding reflection peaks and phases of the sample are measured at different incident angles by using linear antenna and circular polarized antenna. In addition, we change the direction of incident wave vector by rotating the sample and measure the reflection properties again. From two measurement results, obviously, the DB boundary metamaterial possesses a good symmetric property. These experiment results agree well with the numerical simulations. Finally, we make a conclusion that it is feasible to realize the DB boundary at 10 GHz by our proposed metamaterial. 4. Designing an invisible optical device with imaging at the same time through conformal mappingBased on conformal mapping, the Zhukowski mapping can set up a connection between the two spaces, i.e., virtual space(w-space) and physical space(z-space). The w-space has two Riemann sheets connected by a branch cut. We found that when the mirrored Maxwell’s fish eye lens are implemented in the lower Riemann sheet, a conformal cloak could be achieved for both geometry optics and wave optics. Moreover, two kissing mirrored Maxwell fish-eye lens can even be used to design a cloak with a more desirable refractive-index profile. Meanwhile, good imaging effect could be observed in such devices, where it does not need to put the drains inside the device as the branch cut itself can serve as drains. Finally, the device can also perform some illusion optical effects, such as making two sources like one.