为使成像光谱仪能在复杂振动环境和宽温(5~35 ℃)下使用,基于Offner同心结构凸面光栅的光学系统,研制出短波红外成像光谱仪系统。为了验证结构设计的合理性,利用Patran & Nastran对仪器光机结构进行模态分析、静载分析及热致响应分析,并采用广义逆矩阵方法对静载响应分析结果进行处理,得到仪器光学元件的面形变化和刚体位移数据。在0~40 ℃温度范围和4 g加速度载荷下,仪器光学面形变化的方均根(RMS)值小于34 nm,各镜之间相对位置变化小于0.05 mm,各镜偏心小于0.05 mm,满足仪器面形和刚体位移公差要求。振动实验表明,成像光谱仪的一阶模态为559 Hz,远高于一般环境激励,其刚度满足使用要求。温度实验表明,宽温范围内波长极值漂移为0.306 pixel,光谱带宽极值变化为0.493Δ(Δ为吸收峰的半峰全宽)。工程分析和实验验证了该结构的环境适应性,这对仪器工程化具有重要的实用价值。

In order to enable imaging spectrometer to be used in a complex vibration environment and a wide temperature range (5-35 ℃), we designed a short-wave infrared imaging spectrometer based on an optical system of convex gratings using Offner-type concentric structure. Patran & Nastran was used to conduce modal analysis, static load analysis, and thermal response analysis with respect to the optical-mechanical structure of the instrument to verify the rationality of structure design. Further, the generalized inverse matrix method was used to process the results obtained based on static load response analysis to obtain the surface deformation and rigid body displacement data with respect to optical element of the instrument. Under temperature of 0-40 ℃ and an acceleration load of 4 g, the root mean square (RMS) with respect to the optical surface deformation is less than 34 nm, the relative position change between the mirrors is less than 0.05 mm, and the eccentricity of mirrors is less than 0.05 mm, satisfying the requirements for the surface shape and rigid body displacement tolerance of the instrument. The vibration tests denote that the first mode of the imaging spectrometer is 559 Hz, which is considerably higher than that of general ambient excitation. The stiffness of the imaging spectrometer also satisfies the application requirement. The temperature experiments denote that the extreme wavelength drift is 0.306 pixel in a wide temperature range and that the extreme spectral bandwidth change is 0.493Δ, in which Δ is full width at half-maximum (FWHM). Furthermore, the environmental adaptability of the structural design is verified via engineering analyses and experiments, resulting in important practical value for instrument engineering.