Sub-wavelength matter’s interaction with far-field light is highly relevant for both fundamental scientific research, as well as many commercial, medical, and defense applications. For example, quantum computation depends on single identical photons produced by quantum dots characterized by far-field sources. Exoplanet detection uses cameras on Earth comprised of micron sized pixel arrays to capture far-field emission of stars. In this thesis, improving the enhancement between far-field and subwavelength matter is explored for broadband and low loss applications. The applications covered in this thesis are single photon generating quantum dots, integrated nanophotonic devices, short-wave infrared cameras, and neuromorphic inverse design. The enhancement of quantum dots currently depends on solid immersion lenses, photonic pillars, and resonant structures. However, fabrication difficulties, low enhancement, positioning restrictions and spectrum alignment makes it difficult to characterize the quantum dots with far-field sources. This thesis provides a broadband, low-loss solution by utilizing the photonic nanojet to enhance far-field interaction with quantum dots.The photonic nanojet can couple far-field emission to subwavelength spots and fabricate nanophotonic structures using photolithography. The nanostructures are highly subwavelength and difficult to couple to with far-field sources. Aligning a photonic nanojet to the nanophotonic structure is not practical for an array of devices because the microspheres that produce photonic nanojets are around a micron in size. Instead, this thesis produces high enhancement between nanophotonic structures and far-field beams by embedding microspheres in transparent polymers. Flat lenses, and microlens arrays provide possible solutions for pixel-far-field enhancement in cameras. However, microlens arrays based on semiconductor materials must be thin to achieve long focal lengths. Current processing technology is incompatible with making short-wave infrared camera materials thin for long focal length microlenses. Additionally, both flat lenses and microlenses must focus beyond the diffraction limit to enhance far-field and highly subwavelength pixel interaction. This thesis provides an oxide solid immersion lens solution compatible with camera processing, coupled with a subwavelength focal spot reflective lens. Designing a nanophotonic structure which combines near-to-far-field coupling with other functionalities is a major challenge. New approaches in inverse design is highly relevant, but the majority do not include non-linearity and are also inefficient. Here, a new method is proposed based on time-domain artificial neural network which is highly efficient and capable of two dimensional and nonlinear inverse design.

Creator

• Hamilton, Travis

DOI

• https://doi.org/10.21985/n2-e5bh-4q98

Subject

• Electrical engineering

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:15669
• etdadmin_upload_837670

Date created

• 2021-01-01

Resource type

• Dissertation

Rights statement

• In Copyright