Nonlinear Metasurface for Broad-angle Photon-pair Generation
Date
2023
Authors
Jiang, Yuxin
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Entangled photons have found extensive applications in various quantum information technologies. Traditionally, entangled photons are generated through spontaneous para- metric down conversion (SPDC) in bulky nonlinear crystals. The demand for miniaturized quantum optical devices has led to the development of nonlinear metasurfaces (NMs) as a potential replacement for these nonlinear crystals. NMs are 2D arrays of nanoresonators integrated with ultrathin nonlinear material films. By manipulating the geometry, mate- rial, and arrangement of nanoresonators, it is possible to tailor the resonant behavior of the NM and thereby control various nonlinear optical processes. Nonetheless, the spatial emission angles of photons from previously studied NMs were inherently constrained due to the strong angular dispersion of optical resonances. To be effectively used in quantum imaging applications, it is crucial to achieve broad-angle SPDC emission, which provides a wide field of view (FOV) and superior resolution. This project aims to pioneer the development of NMs capable of broad-angle SPDC emission. Broad-angle emission necessitates a flat resonance band in the transverse momentum space. Two NM designs were formulated to control the coupling between optical reso- nances and modify the photonic band structures. Through careful design of the meta- surface parameters, flat resonance bands were created in both NM designs. We employed finite element modelling of electromagnetic waves to simulate SPDC emission properties from the designed flat-band NMs. Our optimal results demonstrated uniform emission of photon pairs within a 6° FOV, yielding a total emission rate of 539 Hz/mW, which is approximately 36 times higher than the previously reported values. The broad-angle SPDC emission has proved robustness against variations in experimental parameters within the achievable limits. Following the fabrication of these structures, we are progressing with experiments to directly demonstrate the broad-angle photon-pair generation with non-classical correlations. Our research outcomes hold the potential to open new opportunities for applications in free-space quantum optics, including quantum imaging and quantum communication.
Description
Keywords
Nanophotonics, Nonlinear optics, Quantum optics
Citation
Collections
Source
Type
Thesis (Honours)
Book Title
Entity type
Access Statement
License Rights
Restricted until
Downloads
File
Description