The Optical Design Based On Double-Layer Binary Optical Elements

With the development of optical technology,optic-mechanical-electric technology becomes a trend.An integrated,arrayed and miniaturized optical system was required.Binary optical element attracts intentions for its unique properties.Double-layer binary optical element not only has light weight and unique properties,but has high diffraction efficiency over wide wavelength range.Double-layer binary optical element is an important trend of binary optical element or diffractive optical element.Based on scalar diffraction theory,this paper analyzes the diffraction efficiency of binary optical element and double-layer optical element.Double-layer optical element has high diffraction efficiency over wide wavelength range.The fabrication errors of double-layer optical element are very complex.This paper analyzes the diffraction efficiency of double-layer binary optical element with height errors,periodic errors and mask fabrication errors.Annulus errors,misalignment errors and angle errors have a big influence on the diffraction efficiency of double-layer binary optical element,but no one reports those.This paper changes double-layer binary optical element which has these fabrication errors into transmittance function and operates the transmittance function with Fourier transformation.This paper has a try on the key problem which solves the diffraction efficiency of double-layer binary optical element.This paper founds an analysis errors model which can analyze fabrication errors automatically and provide a method to analyze double-layer binary optical element.This paper designs an optical system with binary optical element and an optical system with double-layer binary optical element,respectively.After comparing the performance of two optical systems,the result shows that the optical system with double-layer binary optical element has high diffraction efficiency of 99% over all wavelength range.Considering kinds of fabrication errors,the diffraction efficiency of the optical system with double-layer binary optical element can still be 96.8%.But the diffraction efficiency of the optical system with binary optical element can only be 89.6%.