Fabrication And Application Of Large-area Sub-wavelength Gratings

Because of the special property on diffraction,sub-wavelength gratings have been studied for a long time.Their zero order diffracted lights have high brightness,good monochromaticity and very small observation angle,which makes them produce a color-change phenomenon.This phenomenon could be applied in many fields,especially in the anti-counterfeit technologies.Sub-wavelength gratings have outstanding features on the anti-counterfeit field.It is also drawing people's attention in the biomedical science field.In this paper,an analysis on the diffraction of sub-wavelength gratings is made by the rigorous coupled wave theory.A model of the diffraction of sub-wavelength gratings is established and the efficiency of diffraction is calculated.According to the simulation results,a kind of large-area sub-wavelength gratings is designed.Then the templates of large-area sub-wavelength gratings are fabricated successfully by a series of micro-nano manufacturing process,including EBL,ICP,nano-imprint and elctroforming.At last,a template of micro ruler based on sub-wavelength gratings is made,which applied in the biomedical science field.In the fabrication process above,many problems caused by large area layout are solved.In this paper,the sub-wavelength gratings applied in both anti-counterfeit and micro ruler have excellent photochromic phenomenon.So they have good advantages in these fields.Sub-wavelength gratings have accurate structure and special diffraction effects,therefore it is very hard for others to copy or forge them.There haven't been reported in any paper yet that sub-wavelength gratings of large-area are made,as same as the micro ruler in biomedical science.It is a big step to put the sub-wavelength gratings' applications to other fields.