Dissertation Title: “Compact Lens Technologies: Curved Image Sensors and Volumetric Imaging Efficiency”
There are many exciting developments in optical technologies for imaging systems including freeform surfaces, printed lenses, molded aspheres, metasurface optics and complex gradient-index materials. In many cases, these new technologies seek to do the same thing – make lenses better, smaller and/or cheaper. We have introduced a novel metric, the volumetric imaging efficiency (VIE), that provides a framework to compare lens technologies in the context of their performance (i.e. resolution) and size. We used this metric to survey ~3000 lenses, mostly conventional bulk optics, and then compare two emerging technologies – metasurface optics and curved image surfaces. Through this comparison, we show that the VIE is a robust, high-level metric that allows comparing disparate lens types and to identify opportunities enabled by new technologies. Next we extend this metric to consider optical throughput including transmission, scattering and diffraction losses that degrade imaging performance through the volumetric information capacity efficiency (VICE). The VIE analysis shows >100 fold reduction in optic size when imaging onto deeply curved image surfaces but sampling those surfaces remains a challenge. In the remainder of this thesis, we develop fabrication and detector technologies to enable the direct fabrication of curved image sensors. We develop techniques to pattern metal interconnects on plastic prior to deforming to curved surfaces. These techniques combined with existing transfer patterning techniques capability required to fabricate simply-interconnected image sensors onto near-hemisphere surfaces. Last we develop a novel frustrated organic photodiode (F-OPD)) structure that is fabricated as a single monolithic stack and easily scalable into non-planar imaging circuits using self-aligned cross-hatch interconnects to form the pixel array. We design, fabricate and characterize the F-OPD including spectral response, dynamic range, dark current and uniformity. We conduct image sensor simulations and show this novel imaging circuit can be scaled into moderate sized arrays to give compact, wide-angle coverage ideal for applications like security monitoring, machine vision, autonomous navigation and target tracking.
Major: Optics and Photonics PhD
BS: 2014, School of Astronautics, Harbin Institute of Technology
MS: 2018, UCF CREOL,The College of Optics and Photonics
Committee in Charge:
Dr. C. Kyle Renshaw, Chair
Dr. Shin-Tson Wu
Dr. Jayan Thomas
Dr. Shuo "Sean" Pang
Dr. Yajie Dong
Approved for distribution by Dr. C. Kyle Renshaw, Committee Chair, on May 3rd, 2022.
The public is welcome to attend.