Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Hamidreza Ramezani

Second Advisor

Dr. Nicholas Dimakis

Third Advisor

Dr. Volker Quetschke


In this thesis, we explore an application of a non-Hermitian acoustic system with tunable loss in filtering specific frequencies from an upcoming signal at will. Using the commercial computational software, we design our proposed tunable filter made of a phononic super-lattice. The super-lattice consists of two sublattices connected in series. The first sublattice is Hermitian, whereas the other can be Hermitian or Non-Hermitian depending on the amount of loss induced in it. By introducing the loss in the system, we observe the generation of absorbed resonances that can be seen in the reflection spectrum. The range of the filtered frequencies can be controlled by adjusting the degree of non-Hermiticity and designing the first sublattice's resonances. The resonances in the first sub-lattice can be adjusted by increasing or decreasing the number of unit cells in the sub-lattice. Our tunable acoustic filter can be extended to higher frequency ranges, such as ultrasound and other areas, such as photonics. In addition, we explore the geometry-induced non-Hermitian mode couplings and study the different modes in a system of acoustic ring resonators with induced loss and study the field localization within the system.


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