界面折射率不一致对显微成像穿透深度的限制

Limit Penetration Depth of Microscopic Imaging Caused by Focusing Light Into the Bulk Specimen Through Planar Interfaces Between Materials of Mismatched Refractive Index

在运用共焦显微术及低相干显微成像术等进行光学断层成像时,要将光束聚焦到样品内部以便实现光学断层成像,然而由于生物组织等的折射率与盖玻璃以及浸液不同,因而会引入很大的球差,从而使入射电磁波发生畸变.分析了由于多层折射率不一致而引入的球差的大小,并运用所得的公式计算了折射率不一致对光在样品中穿透深度及焦面附近光场分布的影响.

Applications of confocal scanning microscopy and low coherence tomography in the biological and material sciences for optical-sectioning imaging require focusing light into the bulk specimen. However, the differences of refractive indices among biological tissues, the cover slip and immersion medium cause the strong spherical aberration and make the electromagnetic distribution in the focal region distorted. The spherical aberrations caused by focusing the light deeply into the specimen through multilayer medium with different refractive index are analyzed. The results are used to calculate the limit penetration depth of microscopic imaging caused by focusing light into the bulk specimen through planar interfaces between materials of mismatched refractive index. The effect of spherical aberration on electromagnetic distribution in the focal region is also discussed.