Ag/Ge核壳颗粒的结构设计及红外光学特性的理论研究

Structure design and theoretical study on infrared optical properties of Ag/Ge core shell particles

为获得符合光谱选择性辐射红外隐身需求的颗粒,利用Mie散射理论和有限元仿真分别对Ag/Ge核壳结构的红外光学特性进行计算。研究了不同Ag内核和Ge外壳尺寸组合下颗粒消光效率峰值随波长的变化。在6.5μm等值线上等间隔的选取不同尺寸组合,通过对比消光效率曲线确定了0.3/0.848μm的核壳结构为主要研究对象。不同计算方法获得的消光效率曲线形状十分近似,消光峰均位于6.5μm处,消光效率峰值分别为16.6和16.1,验证了计算结果的可靠性。对比颗粒在不同波长入射场下的三维远场辐射及电磁功率损耗情况,发现其在6.5μm处具有更强的辐射强度和功率损耗密度,说明此时颗粒与入射场能够发生强烈的共振作用,可用于该波段红外辐射的选择性吸收。

To obtain particles that meet the requirements of spectral selective radiation for infrared stealth,the infrared optical properties of Ag/Ge core-shell structures were calculated using Mie scattering theory and finite element simulation,respectively.The peak extinction efficiency of particles with different Ag core and Ge shell size combinations was studied.The extinction efficiency curves of different size combinatorial calculators were selected on the contours of 6.5μm,and the 0.3/0.848μm core-shell structure was determined by comparison.The extinction efficiency was calculated by Mie scattering theory and finite element simulation.The curves of the two methods are very similar.The extinction peaks are all at 6.5μm,and the peak extinction efficiency is 16.6 and 16.1,respectively,which verifies the reliability of the calculated results.By comparing the three-dimensional far-field radiation and electromagnetic power loss of particles in different wavelength,the particles have stronger radiation intensity and power loss density at 6.5μm.The results indicate that the particle have a strong resonance with the incident field,which can be used for the selective absorption of infrared radiation in this band.