Date of Award
Open Access Dissertation
Doctor of Philosophy in Electrical Engineering (PhD)
Administrative Home Department
Department of Electrical and Computer Engineering
Committee Member 1
Committee Member 2
Committee Member 3
The first two decades of the 21st century witnessed the emergence of “metamaterials”. The prospect of unrestricted control over light-matter interactions was a major contributing factor leading to the realization of new technologies and advancement of existing ones. While the field certainly does not lack innovative applications, widespread commercial deployment may still be several decades away. Fabrication of sophisticated 3d micro and nano structures, specially for telecommunications and optical frequencies will require a significant advancement of current technologies. More importantly, the effects of absorption and scattering losses will require a robust solution since this renders any conceivable application of metamaterials impracticable. In this dissertation, a new approach, called Active Convolved Illumination (ACI), is formulated to address the problem of optical losses in metamaterials and plasmonics. An active implementation of ACI’s predecessor the Π scheme formulated to provide compensation for arbitrary spatial frequencies. The concept of “selective amplification” of spatial frequencies is introduced as a method of providing signal amplification with suppressed noise amplification. Pendry’s non-ideal negative index flat lens is intentionally chosen as an example of a stringent and conservative test candidate. A physical implementation of ACI is presented with a plasmonic imaging system. The superlens integrated with a tunable near-field spatial filter designed with a layered metal-dielectric system exhibiting hyperbolic dispersion. A study of the physical generation of the auxiliary shows how selective amplification via convolution, is implemented by a lossy metamaterial functioning as a near-field spatial filter. Additionally the preservation of the mathematical formalism of ACI is presented by integrating the hyperbolic metamaterial with the previously used plasmonic imaging system. A comprehensive mathematical exposition of ACI is developed for coherent light. This provides a rigorous understanding of the role of selective spectral amplification and correlations during the loss compensation process. The spectral variance of noise is derived to prove how an auxiliary source, which is firstly correlated with the object field, secondly is defined over a finite spectral bandwidth and thirdly, provides amplification over the selected bandwidth can significantly improve the spectral signal-to-noise ratio and consequently the resolution limit of a generic lossy plasmonic superlens.
Ghoshroy, Anindya, "Superresolution Enhancement with Active Convolved Illumination", Open Access Dissertation, Michigan Technological University, 2021.