采用双离子束溅射物理沉积方法, 通过修正线性渐变沉积速率制备了高透过率、高色散系数的线性渐变滤光片。在不同材料的膜厚修正过程中, 通过匹配高低折射率材料的线性渐变趋势来减小两种材料的失配误差。利用微小光斑测试方法获得了线性渐变滤光片的线性渐变光谱数据, 使用扫描电子显微镜表征了滤光片的表面形貌及微观结构。测试结果表明: 制备的线性渐变滤光片各个位置的中心波长峰值透过率均达到85%以上, 其工作波长为650~1 050 nm, 中心波长的线性变化率为20 nm/mm, 线性度误差在5 nm以内, 带外截止度在0.1%以下。制备的线性渐变滤光片不仅具有好的光谱特性, 也具有良好的稳定性, 完全满足滤光片在空间应用时对小型化、集成化和稳定性的需求。

On the basis of dual ion beam sputtering physical deposition method, a Linear Variable Filter (LVF) with a high transmittance and a high dispersion coefficient was fabricated by correction of linear gradual deposition rates. To get good quality, the linear varying trends of the two materials was matched to reduce their mismatch in film thickness correction processing. The spectral data of the LVF were obtained by the small spot method and the surface morphology and microstructure of the LVF were observed by a Scanning Electron Microscope (SEM). Tested results show that an all-dielectric LVF with an operating range of 650-1 050 nm is obtained. In the range of 20 mm length, the center wavelength transmitted through LVF exhibits an excellent linear dependence (20 nm/mm), and the linearity error is within 5 nm along the direction of the wedge. The measured results indicate that the transmittance of the center wavelength is higher than 85%, and out-of-band transmittance is less than 0.1%. The LVF has good spectral characteristics and stability, thus can satisfy the system requirements for miniaturization, integration and stabilization.