Design of complex material structures for light controlRopač, Peter (Avtor) Ravnik, Miha (Mentor) photonicsinverse designmachine learningliquid crystalswaveguideshologramsdiffraction gratingsphotonic crystalsThis thesis explores the design and optimization of complex material structures for controlling light, with a particular focus on soft-matter systems such as liquid crystals. The research utilizes parametric and inverse design approaches to create various optical devices. The work is divided into four main research directions. The first two focus on the parametric and inverse design of solid-state and liquid crystal photonic components. The third concentrates on liquid crystal diffraction gratings, while the final research direction focuses on computer-generated holograms. As part of the first research direction, the parametric design of slow-light dual-periodic photonic crystals is presented, enabling arbitrarily high group indices using a single design parameter. The research topic continues with the inverse design of two-dimensional photonic structures with asymmetric transmission properties, achieved via topology optimization for both silicon and organic platforms. The results are three devices with relatively high asymmetric transmission in a range of wavelengths. The second research focus is the design of novel three-dimensional liquid crystal optical waveguides and their incoupling/outcoupling terminations, which are designed through substrate anchoring patterns that define the director configuration, using a new versatile method based on signed distance functions. Additionally, reconfigurable liquid crystal devices and networks, designed using both parametric methods and specially developed material-constrained topology and signed distance-based shape optimization, are presented, focusing on different low-loss reconfigurable beam-splitting, deflecting, light-focusing, and routing devices. The penultimate research topic introduces highly dispersive liquid crystal diffraction gratings based on geometric phase optics. These are designed via specially developed parametric anchoring patterns that allow for fine-tuning of the diffraction spectra and continuous tuning via external electric fields between a highly dispersive and transmissive state. The topic evolves into the material-constrained topology optimization of soft-matter diffraction gratings, which are designed to diffract light at specific angles. The design approach uses a new method to impose liquid crystal elastic energy related material constraints, which would otherwise be very computationally expensive. The final research topic of the thesis focuses on material-constrained computer-generated holograms, which are designed using a custom topology optimization-based algorithm. Furthermore, multi-target and multi-image holograms for data encoding, encryption, and color holograms, which are optimized with the new method and adhere to the material constraints of liquid crystals, are presented. The thesis bridges theoretical modeling and physical implementation, advancing the fields of inverse design, soft-matter, and solid-state photonics.20252025-10-01 08:15:58Doktorsko delo/naloga174323sl