高数值孔径聚焦光穿过一个固体薄膜过渡区的远场衍射

Far-field Diffraction of a High-numerical-aperture Focusing Light through a Solid Thin Film Transition Zone

运用矢量角谱方法和折射定律导出了高数值孔径菲涅尔波带片(FZP)聚焦光穿过一个固体薄膜过渡区的远场衍射表达式,应用所获得的公式研究了线性和径向偏振光经高数值孔径?-相位FZP聚焦后分别穿过硅薄膜过渡区和玻璃薄膜过渡区后进入空气的远场聚焦特性.结果显示,固体薄膜过渡区的存在,增加了聚焦系统的焦长,提高了FZP对径向偏振光的聚焦质量,降低了FZP对线性偏振光的聚焦质量.

The paper probes into the experiment that the far-field diffraction formula of a high-numericalaperture focusing light through a solid thin film transition zone is awarded from the application of vector angular spectrum method and the law of refraction so as to derive the high-numerical-aperture Fresnel zone plate(FZP). The far-field focusing characteristics of linearly-and radially-polarized beam focused a highnumerical-aperture ?-phase-shifted FZP respectively passing through a transition zone of glass and silicon film into air is studied using the obtained formula. Numerical results show that, owing to the existence of transition zone of solid thin film, the focal length of the FZP is increased, the far-field focusing quality is improved for a radially-polarized beam of incidence but deteriorated for a linearly-polarized beam of incidence.