Work

Holographic optical elements for complex beam transformations

Year: 2025
Type: article
Abstract: In this thesis, we explore the design, fabrication, and application of volume holographic phase elements in photo-thermo-refractive (PTR) glass for two key purposes: expanding the eye-box in augmented reality (AR) displays and controlling optical angular momentum (OAM) modes in laser cavities. Encoding complex phase structures in PTR glass enables efficient beam shaping, multiplexing, and wavefront engineering, offering strong potential in AR displays, optical communications, and structured light. Holographic optical elements (HOEs) recorded in PTR glass exhibit high diffraction efficiency (over 99%), thermal stability, and chemical durability. Combined with low absorption and scattering in the visible and near-IR, these features make them suitable for both low- and high-power laser systems. For AR applications, we developed a compact method to expand the eye-box using volume gratings operating in the Raman-Nath regime. This achieved uniform 2D image replication over a large area, significantly expanding the viewer’s zone while maintaining brightness and optical efficiency. To demonstrate this, we integrated a time-modulated single RGB laser source with a single phase-light-modulator as image generator, reducing system size and mitigating chromatic and spherical aberrations. The phase control of HOEs enables precise image projection without bulky optics, allowing more compact and lightweight AR devices. For OAM applications, we designed a non-resonant Fabry-Pérot (FP) structured cavity with a holographic phase mask (HPM), maintaining the orthogonality of Laguerre-Gaussian (LG) modes that produces a flat, resonance-free spectral response and supports broadband output. This cavity design opens up new opportunities in optical communications, beam shaping, and quantum optics. In general, this work demonstrates the potential of volume holography to reshape optical systems by enabling compact, efficient solutions for wavefront control, structured light, and multimodal beam generation.
Author: Yaraghi, Shaghayegh
Language: English
Open Access status: green
OpenAlex ID: W7111866853
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