高色散系数线性渐变滤光片的研制

Abstract

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 alldielectric 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(20nm/mm),and the linearity error is within 5nm 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 isless than 0.1%.The LVF has good spectral characteristics and stability,thus can satisfy the system requirements for miniaturization,integration and stabilization.