Design and Application of Waveguide Holographic Optical Elements

Holograms formed in photosensitive materials have the ability to store both the intensity and phase information of the construction beams. Compared to the traditional optical systems, a holographic optical element (HOE) has the properties: formation in thin, lightweight films that can be deposited on various substrates; high diffraction efficiency, high transparency, low scatter, the ability to multiplex multiple holograms in the same element, and the potential for mass production by using replication methods. A waveguide HOE is an element that couples light into/out of a waveguide by diffracting light at an angle larger than the critical angle of the waveguide material, making it well-suited for applications such as holographic displays (combiners), holographic solar concentrators, etc. The first application of waveguide HOEs that will be discussed in this dissertation is in the field of solar concentration. Many solar modules have large inactive module surface areas (IM-SA) that are not covered by active PV cells that respond to a waste of the incident solar illumination. In this dissertation, a light management technique to capture the solar energy falling on IM-SA is described using a novel holographic light collector (HLC) consisting of a reflection type volume holographic element and a diffuser. This system shows an increase in energy yield of 6.1% when the IMSA is 12.3% of the entire PV module surface area. Besides, it provides a predicted increase in energy yield of 5.6% and 4.9% with, respectively, single-axis tracking and fixed solar arrays. Another application of the waveguide HOE is in the eye-tracking system working with augmented reality (AR) eyewear. Many sensing operations in AR systems require the use of wave-lengths in near-infrared (NIR) (750 nm - 900 nm). These wavelengths typically exceed the sensitivity range of available commercial holographic material (450 nm – 650 nm), which complicates the design of optical elements that have focusing power since in this case, significant aberrations result when the reconstruction wavelength differs from the construction wavelength. In this work, several novel methodologies for designing a waveguide hologram imaging system in NIR are described that use: wavefront reconstruction, optimized point source locations, Zernike polynomial decomposition, image evaluation through raytracing, collimation capability optimization, holographic lens recording setup with cylindrical lenses/mirrors, and rapid HOE replication system. Waveguide HOE in-coupler designed and fabricated using a conventional point-source object and reference beams for construction had an image resolution of ~3 lp/mm when applied with a multiplexed HOE out-coupler. However, with the improved design and construction methods presented in this work, an image resolution of > 10 lp/mm with high contrast is demonstrated. In addition to the design optimization methods, a technique for replicating waveguide holograms is discussed. Finally, a dynamic diffraction efficiency monitoring (DDEM) method used to track the dif-fraction efficiency evolution of a HOE during the exposure process was developed and experimentally validated. This technique allows both controlling of the exposure process to optimize the diffraction efficiency as well as studying the diffusion process in holographic photopolymers. The DDEM system was used to optimize the recording of five multiplexed out-coupling HOEs and resulted in a component with uniform consistent diffraction efficiency for five holograms. This would have been difficult or impossible to do without the DDEM technique. A patent was filed on this technique on 4 May 2021.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Graduate College

Grantor dc:publisher

The University of Arizona.

Year dc:date.issued

2021

Author dc:creator

• Zhao, Jianbo

Advisor dc:contributor.advisor

• Kostuk, Raymond

Committee members dc:contributor.committeemember

• Potter, Kelly
• Djordjevic, Ivan

• augmented reality
• eye-tracking
• hologrpahic optical element (HOE))
• solar concentration
• volume hologram
• waveguide HOE

Statement dc:rights

• Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10150/660192

OAI identifier oai:identifier

oai:repository.arizona.edu:10150/660192