Cr光栅掩模对金属平板超透镜成像质量的影响

Effect of Cr Grating Mask on the Imaging Characteristics of Metal Superlens

利用有限元法并结合射频磁控溅射法制备不同厚度Cr膜的透光率的研究,模拟了金属平板超透镜近场成像特性.研究了作为"物"的Cr光栅掩模厚度、占空比对超透镜成像质量的影响.研究结果表明:成像系统的对比度随光栅掩模厚度的增加而增大,当厚度大于50 nm,达到一个稳定值;在相同掩模厚度下,成像系统的像平面随着光栅线宽W的增加而变远;在相同厚度变化范围内,W越大,对比度的变化范围(△C)和像平面位置的变化范围(△y)也都越大,但前者变化更大.研究表明:Cr光栅掩模的厚度、占空比对成像质量有明显的影响.

Based on studying the transmittance Cr films with different thicknesses deposited by radio frequency Magnetron Sputtering,we use the finite-element method to perform full wave simulations of the electromagnetic field,and mainly study the influence of Cr mask thickness and duty ratios on the metal superlens image quality. The research results show that the contrast of the imaging system is increased with the increasing thickness of the mask,and tended to stability when the thickness of the mask exceeded 50 nm.Fixed the thickness of mask,the image plane got further with increasing line width of grating. When the line width of grating increased,the variation ranges of contrast ration and the image plane increased,however the former is more obviously. Therefore,line width has obvious influence on the contrast ration of image.