Research On Characteristics Of Photonic Crystal Microcavity Based On Black Phosphorus

Optical microcavity is a basic optical element with simple structure and wide application.It's very important that extremely small size and high integration for optical devices.The optical microcavity can meet the requirements which the size is generally between a few microns to a few hundred microns.At the same time,it has a good quality factor and extremely low model volume.These advantages make it develop rapidly,not only in traditional optics,but also in quantum information and integrated quantum chips.Next,select the two-dimensional material black phosphorus(BP)to create four photonic crystal microcavity structures.The transmission characteristics of these structures are studied on the basis of surface plasmon theory.It provides ideas for the application of BP in optical devices.First,two types of one-dimensional photonic crystal microcavity structures based on BP were constructed.One is the periodic Bragg grating,which is composed of BP and silicon dioxide(Si O₂).The influence of the number of cycles,cavity length and dielectric layer thickness on the band gap is analyzed.Later,a defect layer was added,and the relationship between structural parameters and microcavity characteristics was analyzed based on the local characteristics of photonic crystals.The second is that BP is used as the material of the defect cavity.The influence of the number of cycles and cavity length on cavity characteristics is studied.And the different structures of the media on both sides of the defect layer were compared.The results show that these two structures are simple in structure,and have small size and outstanding characteristics.And the mode field energy excited by incident electromagnetic waves is highly localized in the microcavity.Secondly,a dielectric-BP-dielectric surface plasmon photonic crystal microcavity is constructed.BP is selected to replace the metal in the traditional waveguide structure.Combining the defects in the center position,a novel waveguide microcavity structure is obtained.The influence of structural parameters on the characteristics of the microcavity is analyzed using the finite difference time domain method.The performance of the microcavity is improved by selecting the structural parameters.At last,a microcavity with a resonance wavelength of 574nm is obtained,the quality factor is 1223,and the mode volume is 3.4×10^-4(?/nm)³.The liquid crystal cell is placed in the defect cavity,and a significant relationship between the applied voltage and the resonance wavelength is obtained.It is determined that the structure can be applied to the filter.Finally,a BP-dielectric-BP type surface plasmon photonic crystal microcavity was constructed.The transmission and electromagnetic field distribution characteristics of this structure are analyzed and studied.The relationship between quality factor,model volume and structural parameters is studied according to the finite difference time domain method.The results show that a better quality factor and sub-wavelength model volume are obtained by adjusting the parameters.The value of Q/V is as high as 5.79×10⁶.It has important research value for effectively reducing the structural size of photonic devices and breaking the diffraction limit.