用两区π-相位滤波器改善超半球形固体浸没透镜显微系统的成像特性

Improving the Image Characteristics of the Supersphere Solid Immersion Lens Microscopy Systems Using a Two-zone π-phase Filter

利用矢量衍射理论分析了π-相位滤波器在超半球形固体浸没透镜显微系统中的超分辨特性.结果显示,光斑的增益、Strehl率和边瓣强度随相位区域边界呈现出同步的、只一个周期的振荡性变化.从辐射场和速逝场的角度解释了这种变化的原因.对于近场显微,速逝场起决定性作用.π-相位滤波器的相位区域边界角大于临界角时,才能产生较大的超分辨作用.滤波器边界参量等于0.743(对应的角度大于临界角)的π-相位滤波器,可以使系统分辨率提高16%.

Super-resolution in the supersphere solid immersion lens （s-SIL） microscopy systems with a highnumerical aperture was presented using a two-zone π-phase filter. Numerical results show that the spot gain,Strehl ratio, and sidelobe intensity of the system occur an in-phase and only-one-period oscillatory behavior as the zone-boundary parameter of phase. The explanation to these phenomena was given according to radiative and evanescent field idea. The evanescent field dominated in the optical near-field microscopy. The great super-resolution can be produced when the zone boundary angle of the π-phase filter is larger than the critical angle at the plane interface of the s-SIL. The example presented shows that the resolution of the s-SIL system with 30° critical angle is improved by 16%when the zone-boundary parameter is 0. 743 （44.6°）.