Department of Physics and Astronomy, University of Exeter, Exeter, UK.
J Microsc. 2022 Nov;288(2):95-105. doi: 10.1111/jmi.12991. Epub 2021 Jan 13.
Remote focusing (RF) is a technique that greatly extends the aberration-free axial scan range of an optical microscope. To maximise the diffraction limited depth range in an RF system, the magnification of the relay lenses should be such that the pupil planes of the objectives are accurately mapped on to each other. In this paper we study the tolerance of the RF system to magnification mismatch and quantify the amount of residual spherical aberration present at different focusing depths. We observe that small deviations from ideal magnification results in increased amounts of residual spherical aberration terms leading to a reduction in the diffracted limited range. For high-numerical aperture objectives, the simulation predicts a 50% decrease in the diffracted limited range for 1% magnification mismatch. The simulation has been verified against an experimental RF system with ideal and nonideal magnifications. Experimentally confirmed predictions also provide a valuable empirical method of determining when a system is close to the ideal phase matching condition, based on the sign of the spherical aberration on either side of focus.
远程聚焦（RF）是一种极大地扩展光学显微镜无像差轴向扫描范围的技术。为了使 RF 系统的衍射极限深度范围最大化，中继透镜的放大率应该使得物镜的光瞳面彼此准确地映射。在本文中，我们研究了 RF 系统对放大率失配的容忍度，并量化了在不同聚焦深度处存在的残余球差量。我们观察到，与理想放大率的微小偏差会导致残余球差项的增加，从而减少衍射极限范围。对于高数值孔径物镜，模拟预测放大率不匹配 1%会导致衍射极限范围减少 50%。该模拟已通过具有理想和非理想放大率的实验 RF 系统进行了验证。实验证实的预测还提供了一种有价值的经验方法，用于根据焦点两侧的球差的符号确定系统何时接近理想的相位匹配条件。
