Manipulation of quantum emitters using optical nanofiber tips

Abstract

The crucial aspect of quantum information science is the efficient coupling of single newlinephotons from a single quantum emitter into a single-mode fiber for a quantum newlinenetwork. Recently, fiber-based platforms such as optical nanofibers (ONFs) and newlineoptical nanofiber tips (ONFTs) have emerged as promising candidates for the newlineefficient coupling of single photons. Despite extensive experimental research on newlinecoupling single photons into guided modes of the ONF, no experimental studies newlinehave been conducted using the ONFT for this purpose so far. ONFTs are vacuumclad newlinesilica fibers with sub-wavelength diameters at one edge. Due to the strong newlineconfinement of the electromagnetic field at the tip, the ONFT can significantly newlinemodify the spontaneous emission of the quantum emitter into guided modes of newlinea single-mode fiber. In addition to coupling, a technology by which information newlinecan be readily encoded into the photonic degrees of freedom for exchange between newlinedistant quantum nodes is crucial. Photon degrees of freedom are solely associated newlinewith their quantum properties, and polarization is a significant property of the newlinephoton. The polarization characteristics of fluorescence photons from a quantum newlineemitter coupled to an ONFT have not been investigated. This thesis presents newlinedetailed simulations and systematic experiments for efficiently coupling fluorescence newlinephotons from quantum emitters into guided modes of ONFTs and their newlinepolarization response. newlineFirst, I perform numerical simulations to determine coupling efficiency (and#951;) newlinefor the ONFT and a single dipole source (SDS) system. For the radially oriented newlineSDS at the center of the facet of the ONFT, the maximum and#951;-value of 44% is newlinefound for the emission wavelength at 620 nm. Additionally, the SDS position newlinedependence in transverse directions on the facet of the ONFT in view of keeping newlineexperimental ambiguities is investigated. It is found that the SDS position in newlinetransverse directions on the facet of the ONFT does not affect the and#951;-value significantly, newlineminimizing experimental ambiguities. The polariz