摘要
为了获取足够的目标信息，同时避免宽光谱色差和结构的复杂性，本文充分利用太赫兹波的科学价值，建立了谐衍射／折射太赫兹多波段成像系统。针对谐衍射元件独特的色散性质，将谐衍射透镜应用于14～50“m太赫兹成像系统中，使系统在15．8～16．2μm，18．5～20μm，23～25μm，30．5～33．5μm和46-50μm5个谐振波段内的轴向像差最大为0．75mm。由于各谐振波段内的放大率是波长的函数，图像重构时将引起像元的配准误差，利用光学二组元法设计的变焦结构成功地解决了这一问题。设计结果表明：系统像高恒定为6．74mm，变焦结构还具有很好的像差补偿作用；在10lp／mm时，光学传递函数在5个谐振波段内均达到衍射极限，实现了轻小、便携、易加工的设计要求。
In order to get enough information, and to avoid the big chromatic aberration of wide spectrum and the complexity of optical system, a harmonic diffractive/refractive optical system was estab- lished by making the best use of science value of terahertz. A 14-50μm terahertz wave was integrated into multi-band imaging system based on the special large dispersion capability of harmonic diffractive element, and the longitudinal aberration was simultaneously limited to less than 0.75 mm in the five harmonic wave bands （15.8-16.2 μm, 18.5-20 μm, 23-25μm, 30.5-33.5 μand 46-50 μm）. In each harmonic wave band, the magnification changed as a function of wavelength, which created image registration error. To compensate this shortcoming, a zoom optical system was designed by binary optical component. The design results show that the image height keeps 6.74 mm in every harmonic band and the zoom optical system can realize aberration compensation action. In the five bands, each optical transfer function approaches to the diffraction limit in 10 lp/mm. These results indicate that the system can meet the requirements for portability, minitype and easy fabrication.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2008年第11期2065-2071,共7页
Optics and Precision Engineering
基金
国家863高技术研究发展计划资助项目(No.2006AA703405G)
关键词
太赫兹波
谐衍射透镜
多波段成像
变焦系统
成像系统
terahertz
harmonic diffraction lens
multi-band imaging
zoom system
imaging system
