Rigorous designs of nano-optical couplers and absorbers with photonic crystals involving irregular arrays and nonidentical elements

Yazar, Şirin
This thesis presents design and analyses of compact and effective nano-optical couplers and absorbers based on photonic crystals. Single-input and double-input nano-optical couplers that provide electromagnetic wave transmission in desired directions are designed, and important parameters regarding their transmission efficiency are investigated. These designs are further cascaded by adding one after another to create nano-optical transmission systems, whose transmission characteristics are also examined. In addition, nano-optical logic-gate couplers that perform certain logic operations, as well as nano-optical isolators that transmit electromagnetic waves only in the forward direction are designed and analyzed. On the other track, nano-optical absorbers are designed by combining metal plates with anti-reflective coatings made of photonic crystals. Anti-reflective absorber designs, which both confine high power density within themselves and prevent back reflections that are potentially harmful to other objects and sources, are successfully obtained. For all these nano-optical structures, electromagnetic simulations are performed by using an efficient implementation of the multilevel fast multipole algorithm. In addition, all designs are achieved by performing heuristic optimization via genetic algorithms. The numerical results show that it is possible to design and further improve efficient nano-optical couplers and absorbers with relatively simple geometries based on the principles of photonic crystals.


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Citation Formats
Ş. Yazar, “Rigorous designs of nano-optical couplers and absorbers with photonic crystals involving irregular arrays and nonidentical elements,” M.S. - Master of Science, Middle East Technical University, 2021.