Study Of Manipulating Electromagnetic Wave Based On One-way Effects And Transformation Optics

Miniaturization and integration are inevitable trends in the development ofoptical communication devices and subsystems. However, in photonic circuits,signal reflection and backscatter arising from defects during the fabricationprocess seriously hinder the large-scale integration of photonic devices.Recently, international attentions have been paid to this problem, andfollowed with the design of nonreciprocal one-way waveguides with highisolation and strong scattering immunity based on time-reversal symmetrybreaking. However, some disadvantages including complex structure, difficultfabrication and so on, have been exposed in these one-way waveguides.Herein, in this thesis, we design a kind of one-way waveguides with simplestructure and deeply study temperature stability, immunity to scattering,tunability via field and controllable nonlinear effects of the one-wayelectromagnetic mode in the one-way waveguide.Furthermore, with the development of meta-material techniques,manipulating electromagnetic wave in the full space such as electromagneticcloaks, electromagnetic black holes, electromagnetic beam splitters andcouplers etc, can be realized. Based on transformation optics andmeta-material, the control of electromagnetic wave in the whole space such aselectromagnetic superscatterer, superabsorber, external cloak, high-directivityantennas and electromagnetic “pass through a wall” have also been deeplystudied in this thesis. Meanwhile, the electromagnetic “pass through a wall”device is fabricated based on transmission line artificial media, and thebroadband functionality of this device is also confirmed for the first time.This thesis is supported by the Key Project of Chinese Ministry of Education and National Natural Science Foundation of China. The detailedresearch contents are as follows:1. One-way magneto-optical photonic crystal waveguides based onsymmetrical structureA new type of one-way (nonreciprocal) photonic crystal waveguide isproposed based on time-reversal symmetry breaking to investigate themanipulation of one-way edge mode.1) A symmetrical nonreciprocal one-way photonics crystal waveguide undertwo equal and opposite magnetic fields is designed to generate one-wayedge mode, which is not influenced by the scatterers (defects).2) The time-reversal phenomenon of one-way edge mode is studied andfound that the time-reversal of edge mode can be realized whendirections of the external magnetic fields are reversed.3) The forbearance of temperature effect in the one-way edge mode isdiscussed. Our results show that the one-way properties of the edge modeare insensitive to the temperature variation from233K to333K.2. Nonlinear effects of one-way (nonreciprocal) photonic interband transitionsThe nonlinear modulation effects of one-way interband photonictransitions have been studied. Numerical calculations of nonlinear two-modeequations show that only the period of such complete inter-band photonictransitions is modulated for the relatively weak nonlinear effect, whileinter-band transitions can be partially or even completely suppressed forrelatively strong nonlinear effect.3. Manipulating electromagnetic wave in the whole space: electromagneticsuperscatterer and superabsorber.The elliptical, eccentric and arbitrary geometry of electromagneticsuperscatterer and superabsorber are investigated by using thetransformation optics and fold geometry. Furthermore, the concept ofelectromagnetic superscatterer is also extended to design waveguideconnectors between two separated waveguides.4. Manipulating electromagnetic wave in full space: external cloaks andhigh-directivity antennas. 1) Two kinds of external cloaks are designed in virtue of transformationoptics together with the complementary media and shifting media. Onecommon trait is that the hidden object can’t be probed from the outside butthey can “see” the outside space. The difference between them is that theexternal cloak based on the complementary media is depended on theanti-object, while the other external cloak based on the shifting media isindependent of anti-object.2) Two kinds of applications such as movable high-directivity antenna androtatable high-directivity antennas are realized by using the complementarymedia. Meanwhile, based on the shifting media, overlapped optics andantenna amplifiers are also studied.5. Manipulating electromagnetic field distribution in full spaceManipulating electromagnetic field distribution in two-dimensional spacebased on the embedded transformation optics1) The field distribution of a point source can be compressed and amplifiedin the two-dimensional space by using the embedded transformation optics.Two kinds of layered lossless waveguide connectors with simple materialparameters, and the experimental verification of the two-dimensionalbroadband electromagnetic “go through a wall” are also realized in thisthesis.2) The point source can also be converted into the case of plane wave withlinear and nonlinear lateral shift by using the embedded transformationoptics.