Model Mechanism Of Gallium Nitride Microcavity

The excellent properties of optical microcavities are due to the way they confine the light field and the absorption of the light wave by the related materials.The Whispering Gallery Mode(WGM)microcavity mainly utilizes the effective potential barrier formed by the refractive index difference at its outer surface to constrain the light field.This unique constraint method makes it have optical characteristics such as high quality factor,small mode volume,low threshold,and narrow linewidth.Compared with traditional resonant cavities,WGM microcavities have better mechanical stability and are more convenient for regulating the internal parameters,making them easier to integrate into optical networks.Semiconductor materials are also one of the hot research directions in the study of optical microcavities.Gallium Nitride(Ga N)material is a typical representative of the thirdgeneration semiconductor materials.It has excellent properties such as wide bandgap,high electron saturation drift velocity,high breakdown voltage,high thermal conductivity,and strong radiation resistance.It can also emit a wide spectrum of light from blue to deep ultraviolet,and has been widely used in the field of semiconductor devices.The research content of this article is to explore the influence of diameter size on the performance of Ga N microdisk lasers and provide reference for the selection of size in practical applications,which is of great significance for on-chip integration of microdisk cavities.The main research content of this article includes the following three points:Firstly,the solution of the resonant wavelength under different modes.A wavelength solution model was established and derived by solving the Maxwell equation group under the boundary conditions,and a characteristic equation with an unknown quantity of resonant wavelength λ was obtained.By using MATLAB to solve this equation,the resonant wavelength of the corresponding mode under different refractive index representations was obtained and analyzed.Secondly,using COMSOL to simulate Ga N microdisk cavities with diameters of 10 μm to 25 μm,the electric field distribution,spectrum,and far-field mode patterns of ideal microdisk cavities with different diameters and thicknesses of 250 nm and 2 μm were obtained.In addition,the light field pattern and far-field mode pattern of the disk with a slit were prepared and simulated,and the farfield mode pattern of the axisymmetric microdisk cavity was compared with that of the slit microdisk cavity.Finally,the three types of losses,mode volume,and finesse of the ideal microcavity were calculated using formulas to determine the decisive loss of the Q value and the influence of the diameter on the finesse.Thirdly,microcavities with corresponding sizes to the simulation were prepared and analyzed through spectral testing and data processing,and the influence of the actual microcavity diameter on the mode number,full width at half maximum,Q value,and finesse was analyzed and compared with the ideal microcavity.Secondly,the mode number of microdisks of various sizes was analyzed.