Electrical and Computer Engineering ETDs

Publication Date

6-25-2015

Abstract

The ability to produce a high quality infrared image has significantly improved since its initial development in the 1950s. The first generation consisted of a single pixel that required a two-dimensional raster scan to produce an image. The second generation comprised of a linear array of pixels that required a mechanical sweep to produce an image. The third generation utilizes a two-dimensional array of pixels to eliminate the need for a mechanical sweep. Third generation imaging technology incorporates pixels with single color or broadband sensitivity, which results in 'black and white' images. The research presented in this dissertation focuses on the development of 4th generation infrared detectors for the realization of a new generation of infrared focal plane array. To achieve this goal, we investigate metamaterials to realize multicolor detectors with enhanced quantum efficiency for similar function to a human retina. The key idea is to engineer the pixel such that it not only has the ability to sense multimodal data such as color, polarization, dynamic range and phase but also the intelligence to transmit a reduced data set to the central processing unit (neurophotonics). In this dissertation, we utilize both a quantum well infrared photodetector (QWIP) and interband cascade detector (ICD) hybridized with a metamaterial absorber for enhanced multicolor sensitivity in the infrared regime. Through this work, along with some design lessons throughout this iterative process, we design, fabricate and demonstrate the first deep-subwavelength multispectral infrared detector using an ultra-thin type-II superlattice (T2-SL) detector coupled with a metamaterial absorber with 7X enhanced quantum efficiency. We also identify useful versus non-useful absorption through a combination of absolute absorption and quantum efficiency measurements. In addition to these research efforts, we also demonstrate a dynamic multicolor metamaterial in the terahertz regime with electronically tunable frequency and gain for the first time. Utilizing an electronically tunable metamaterial, one can design an imaging system that can take multiple spectral responses within one frame for the classification of objects based on their spectral fingerprint.'

Keywords

Infrared, photodetectors, metamaterial absorber

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Brueck, Steve

Second Committee Member

Habteyes, Terefe

Third Committee Member

Peters, David

Fourth Committee Member

Padilla, Willie

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