Principles of Geometric Phase Hologram Optical Devices and Applications to XR Optical Systems

[Seminar Announcement]

• Title: Principles of Geometric Phase Hologram Optical Devices and Applications to XR Optical Systems

• Date and Time: Wednesday, August 7th, 4:00 PM

• Location: Room 2203 (Lecture Room 7, E3-2)

• Speaker: Prof. Kim Hak-Rin (Kyungpook National University)

• The language of the talk/ presentation materials: Korean/ mostly English  

Abstract:

Recent research has actively explored geometric phase hologram (GPH) optical devices, which allow for various optical arbitrary wavefront control under flat optics conditions with the same thin film thickness.

This is possible because, in a birefringent medium with a half retarder condition, a spatial pattern distribution of the optical axis can be formed, allowing the degree of phase delay to have a linear relationship with the positional patterning.

Compared to plasmonic or dielectric meta-surface-based flat optics, GPH devices are advantageous due to their high reliability and ease of large-area thin film processing, as well as significantly lower chromatic aberration dependence. This makes them highly applicable in fields requiring optical wave control over the visible light spectrum, such as displays and imaging.

In this presentation, we will introduce the wavefront control principles of general GPH devices, examples of GPH lens devices being developed in our lab at Kyungpook National University, and the issues that need to be addressed in related fields. Specifically, we will discuss the potential applications in XR optical systems, which demand ultra-lightweight and ultra-thin form factors.

We will explain how general GPH devices can achieve two conditions of wavefront control with conjugate phase relations based on the incident circular polarization condition and the usefulness of switchable optics in stacked device structures. Additionally, we will introduce recent research findings on the potential benefits of forming birefringent conditions under quarter retarder conditions for diversification of wavefront-control sets.