Research on emissivity of concave cavity array surface blackbody based on Monte Carlo ray tracing

As one of the commonly used blackbody types for infrared radiation calibration, the emissivity level of surface blackbody is limited by the surface coating and surface microstructure array. To study the emissivity of surface coatings and the influence of surface microstructure on the emissivity of surface blackbodies, we establish optical and mechanical models of four different array concave cavity surface blackbodies, including triangular concave cavity, quadrangular concave cavity, pentagonal concave cavity, and hexagonal concave cavity arrays. Based on the Monte Carlo ray tracing method, simulation calculations of blackbody emissivity are carried out, with a focus on analyzing the effects of array concave cavity structure type, optical properties of blackbody surface coatings, and height of concave cavity structure on the emissivity of surface source blackbodies. The simulation results show that, under the condition of 100% diffuse reflection coating on the surface and constant concave cavity edge length, for the four types of concave cavity arrays, an increase in coating emissivity or array height can promote the emissivity of the blackbody. When the length of the concave cavity remains constant and the surface emissivity remains constant, the higher the proportion of near specular reflection, the higher the normal emissivity. When the surface optical properties are the same and the array height is the same, for the four structures, the triangular concave cavity structure surface blackbody has a higher emissivity. The simulation results can provide theoretical basis and data support for the design of high emissivity surface blackbody for infrared radiation calibration.