This dissertation explores a new method for creating holographic phase masks (HPMs), which are phase transforming optical elements holographically recorded in photosensitive glass. This novel hologram recording method allows for the fast production of HPMs of any complexity, as opposed to the traditional multistep process, which includes the design and fabrication of a master phase mask operating in the UV region before the holographic recording step. We holographically recorded transmissive HPMs that are physically robust (they are recorded in a silicate glass volume), can handle tens of kilowatts of continuous wave (CW) laser power, are un-erasable, user defined, require no power to operate, can work over a wavelength band ranging from 350 to 2500 nm, and can modify the wavefront of narrow line or broad band coherent sources. The HPMs can be wavelength-tunable by angular adjustment over tens or even hundreds of nanometers. The HPMs incorporate the phase information in the bulk of a volume Bragg grating (VBG) resulting in only a single diffraction order and up to 100% diffraction efficiency. Recording in thick photosensitive medium also enables the multiplexing of HPMs in a single monolithic element. While these HPMs are physically overlapped in the space, they provide independent phase profiles, efficiencies, spectral and angular acceptances. Multiplexing HPMs allows splitting or combining of multiple beams while affecting their wavefronts individually. We also developed a new holographic phase mask of reflective-type. This device provides us the ability of recording RBGs with transversely shifted parts in the larger aperture which upon reconstruction will produce different phases to different parts of the diffracted beam. RBG's diffraction spectrum possesses a very narrow bandwidth, and the holographic recording technique allows to multiplex multiple gratings into a single volume of PTR glass. If each of these Bragg wavelengths is assigned with a specific spatial mode, it can be achieved simultaneous spatial and spectral multiplexing. As a separate research topic, we look at how holographic optical elements (HOEs) can be used for improving the capabilities of the existing generation of head-up displays (HUDs), resulting in smaller, lighter units with a larger eye-box. Currently, surface relief gratings recorded in photosensitive polymers that are susceptible to the environmental conditions are used in HOE-based HUDs. This has an impact on their reliability and overall lifespan. We investigated a specific holographically recorded in the volume of photo-thermo-refractive glass transmissive gratings that generated multiple diffracted beams due to their operation in Raman-Nath regime. The Raman Nath gratings were successfully used to create an array of images because in augmented reality systems, this approach can be used to enhance the size of the exit pupil. These image splitting elements, due to the features of PTR glass, have a great resistance to temperature gradients, mechanical shocks, vibrations, and laser radiation.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2054 |
| Date | 01 January 2022 |
| Creators | Mohammadian, Nafiseh |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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