Quantum Light Source Control Based On Artificial Plasmon Structure

The rapid emergence of information technology has created rigid demand for technical requirements.The requirements for various structures and sensors have become increasingly faster and faster.In order to meet this demand,photons instead of electrons have gradually arised as new information carriers,which leading to a transition from integrated circuit to photonic integration.Optical signals,as information carriers,have multiple advantages such as greater information capacity,faster transmission speeds,and higher fidelity quantum information processing capabilities etc.Among them,quantum optical technology requires strong coherence of single-photon emitters（SPE）.Quantum dots（QDs）,due to their zero-dimensional density of states,exhibit stable and narrow-band emission with wide spectral tunability,making them one of the most promising SPE candidates.However,within the visible and near-infrared range,the lifetime of QDs in free-space radiation recombination is too long and the spontaneous emission rate of a single QD is still too low.Therefore,this thesis attempts to design a plasmon-QD coupling structure based on the excellent light modulation ability of plasmons,aimed to improve the spontaneous radiation performance of SPEs,and to analyze and optimize the relevant parameters at a theoretical level.This thesis mainly investigates the following two aspects:（1）Two plasmonic-NWQD coupling structures with different sizes are proposed.Simulative results show that the Bowtie structure can increase the spontaneous emission of small-diameter NWQDs and overcome the inherent spontaneous emission suppression of NWQDs,with extremely low ohmic losses.The metal plasmonic waveguide-NWQD structure can act as a single-mode waveguide.And improve the spontaneous emission performance of large-diameter NWQDs.Thefactors of the two structures are 52.3and 114,respectively,which is 1040 times and 2280 times higher of the spontaneous emission rate of a single NWQD with the same diameter.Theoretical coupling efficiencies of the structures and conventional waveguides are also calculated to demonstrate their potential for on-chip integration.（2）The enhancement effect of the multi-plasmonic structure on a single NWQD is studied.A new long-distance enhancement mechanism is proposed.Using this mechanism,periodically arranged Bowtie plasmonic antennas can be used to enhance the spontaneous emission of NWQD and direct photon radiation in the vertical direction.The Purcell enhancement factors of the proposed multi-Bowtie-NWQD coupled structure are close to 66.1 and 145.8,respectively.Compared with a single NWQD of the same diameter,the fluorescence was enhanced by 1054-fold and 2916-fold.The predicted collection efficiencies were close to 85%and 80%,respectively（NA=0.5）.Unlike single-photon emitters based on bulky conventional optics,this is a unique SPE source based on a line-array configuration using a surface plasmon-enhanced design with minimal dissipation.In this thesis,a plasmonic structure is used to enhance the spontaneous emission rate and improve the directionality of SPE while retaining high quantum efficiency.The proposed design will pave the way for the development of SPEs and their possible integration with semiconductor optoelectronics.