斜入射条件下微测辐射热计的光学特性研究

针对典型的微测辐射热计单元结构的设计,依据光学导纳矩阵方法,用Matlab软件分析了多层薄膜的光学特性,获得了理论上红外吸收率最大时吸收层的厚度0.1μm和空腔的高度2μm,通过理论计算得到了斜入射条件下红外吸收率随入射角的变化规律,与常规的计算方法——垂直入射条件下得到的红外吸收率相比,它更接近于实际情况,仿真计算结果更加准确。结果表明:器件在8~14μm波段有80%以上的红外吸收率,并且当微桥形变很小时,器件依然有很高的红外吸收率。

Study on optical properties of microbolometers in oblique incidence

The design of typical microbolometer is described.According to optical admittance matrix method,the optical characteristics of multilayer film structure is simulated by Matlab software.The optimal thickness of absorbor film and height of vacuum are obtained when infrared absorptivity rate is maximal,and their values are 0.1 μm and 2 μm respectively.It is reported the infrared absorptivity variation with incident angle’s increasing by theoretic calculating in oblique incidence.Compared with the infrared absorptivity in normal incidence,which is different from the conventional method,this method is closer to the actual situation and can obtain a better simulation result.The results indicate the microbolometer has an infrared absorptivity of more than 80 % in 8~14 μm spectral range.Meanwhile,even when the strain of micro-bridge is very small,the device still has a high infrared absorptivity,either.The simulation result of this paper offered reliable evidence to study microbolometers.