Confocal measurement approach for enhancing lateral resolution using a phase-only pupil

Confocal measurement approach is recently widely used as important tools for measurement of three-dimensional microstructures and surface contours because of its good 3D chromatographic imaging capability. But its lateral resolution is limited by the diffraction effect to about 0.4 mu m only while the axial resolution has reached the nanometer level. A phase-only confocal measurement approach is therefore proposed to enhance the lateral resolution. In this paper, an optimized superresolution phase-only filter is used in a confocal microscopy system to improve the lateral resolution, and the pinhole in the confocal microscopy system effectively eliminates the disturbance of ambient lighting and improves the imaging quality. Simulation results indicate that, an optimized three-zone pupil with G(L)=0.8375 and G(A)=0.99 can make the lateral resolution of CMS 1.18 times better while the axial resolution is almost invariable. So it therefore can improve the applicability of confocal microscopy system.