Research On The Optical Nanocavity Of Ultrasmall Mode Volume

Due to the development of science and technology and the advancement of device fabrication technology,the size of the unit devices used for information processing has been gradually approaching the atomic scale.At the nanoscale,unavoidable quantum effects will make classical information technology come to the end of the Moore's Law.The study of the interaction between the local mode field in nanocavity and the quantum system has become one of the important fields of quantum information science and technology.Design of optical micro-cavity with high quality factor(Q)or small mode volume(Vm)has important applications in the field of optical communication and quantum information.Unique dispersion relations of our hyperbolic metamaterial(HMM)nanocavity enable propagation of large wave vectors result in strong wave confinement.The excitation of coupled localized surface plasmons(LSPs),which have achieved ultrasmall mode volume.Based on the characteristics of HMM,the optical properties of plasmonic cavities such as quality factor and mode volume are discussed.The main contents of this paper are as follows:1.The definition and classification of surface plasmons polaritons(SPPs).Based on the Maxwell's equations,the electromagnetic field distributions of SPP in two-layer and three-layer structure are calculated.The finite-difference time-domain(FDTD)method is used to solve Maxwell's equations,and the Courant stable condition and the simulation software are introduced.2.Introduce the definition of metamaterials,and divide the metamaterials into ? type and ? type according to the different dispersion relations.Two methods for realizing metamaterials are introduced:multilayer and metal rod arrays,and the application of metamaterials to enhance spontaneous emission.3.The main properties of optical nanocavities are the quality factor,the mode volume,and the Purcell factor.Describes the advantages and disadvantages of different kinds by nanocavities,exhibits excellent characteristics of the metamaterial nanocavity.4.The square nanocavities of multilayered Ag and Al2O3 are simulated by using FDTD solutions.The results show that there are two main resonances in the visible range to determine the basic simulation environment.The transmission spectra of the octagonal optical cavity with different radii are discussed.The main resonance is determined by LSPR from the field distribution of resonance.Discusses the transmission spectra of circular optical cavities with different radii and finds the existence of spurious resonance,which shows that non-LSPR modes exist in polygons and circles.5.Changing the rectangles HMM nanocavity length in x and y dimensions separately,we found that the resonant wavelength can be changed,and the cavity length along the polarization direction has the most significant effect on the result.By calculating the mode volume of the nanocavity,we found that the smallest mode volume is 10-6?3,and the ratio of the quality factor to the mode volume(Q/Vm)is up to 107?-3.In addition,we discuss the transmission spectra of nanocavities with different metal filling rates or different shape.It is found that the change of these parameters has little effect on the resonance position of nanocavities.This shows that the stability of the nanocavity allow small errors in the experiment.In conclusion,the special properties of HMM provide a new idea for the study on optical nanocavities of ultrasmall mode volume in the visible range.