Abstract

Imaging is almost synonymous with optics. Imaging is the process of using light to form a tangible or visible representation, an imitation (imitari) of a material property. There are many situations, however, where one can only aspire to 'sense making' rather than forming an image per se. In other words, objects cannot be directly resolved by conventional intensity-based imaging, a situation commonly referred to as 'unresolved imaging'. However, there is still information retained in other properties of light, which can be exposed by other means. In this thesis I will discuss two typical situations: subwavelength and multiple scattering, which are very different in terms of the spatial extent of light-matter interaction. In the subwavelength regime, information can be encoded through both inelastic and elastic interaction processes. When the latter is the preferred approach, observables such as optical phase are determined by the properties of evanescent waves while the measurements are usually conducted in the far-field. I will describe a novel energetic interpretation of the light-matter interaction in this regime, which provides an accurate estimation of the interaction volume of a single scattering event and of the small phase delay it introduces. I will also show how this minute phase occurring in subwavelength scattering can be quantitatively measured with optimal sensitivity by a polarization-encoded common path system and how it enables subwavelength sizing in a label-free fashion. At the other extreme, evaluating the information transfer in multiple scattering regimes is usually constrained by the computational complexity of the problem. I will describe two forward modeling approaches that alleviate these limitations in non-line-of-sight sensing geometries and in coherent illumination methods for imaging through obscurants. These simplifying descriptions also reveal the fundamental limits for information transfer in these two scenarios.

Notes

If this is your thesis or dissertation, and want to learn how to access it or for more information about readership statistics, contact us at STARS@ucf.edu

Graduation Date

2021

Semester

Fall

Advisor

Dogariu, Aristide

Degree

Doctor of Philosophy (Ph.D.)

College

College of Optics and Photonics

Department

Optics and Photonics

Degree Program

Optics and Photonics

Identifier

CFE0009317; DP0026921

URL

https://purls.library.ucf.edu/go/DP0026921

Language

English

Release Date

June 2022

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Open Access)

Download

Included in

Optics Commons

Share

COinS