%0 Journal Article
%T Study of an athermal infrared dual band optical system design containing harmonic diffractive element
%A Qiang Sun
%A Zhaoqi Wang
%A Fengyou Li
%A Hongli Liu
%A Zhenwu Lu
%A Chen Bo
%A Guoguang Mu
%J Chinese Science Bulletin
%@ 1861-9541
%D 2003
%I 
%R 10.1007/BF03183934
%X A harmonic diffractive element (HDE) is first successfully introduced to the athermal system of infrared dual band in this paper. In this system, there are only three lens and two materials, silicon and germanium. When the temperature ranges from  70 ˇăC to 100 ˇăC in the dual band, it can simultaneously accomplish the rectification of the longitudinal aberration in the big field of view, as well as the wave front aberration less than 1/4 wavelength. Modulation transfer function of dual band approaches or attains the diffraction limit. The calculation results show that the spectral properties of the HDE are between refractive and diffractive elements, so we can design a simple dual-band and athermal optical system by selecting the thickness and central wavelength of the HDE exactly. Compared with a conventional refractive optical system, this system not only reduces the demand for high technical levels, but also has a compact structure, few elements, a high transmittance better aberrations performances and athermal character. At the same time, the use of the HDE also offers a new element for the infrared optics design.
%K harmonic diffraction
%K athermal
%K infrared dual band
%K optical design
%U http://link.springer.com/article/10.1007/BF03183934