Refractive Index Determination by Index-Mismatch-Induced Spherical Aberration

摘要

Two-photon microscopy has been successfully applied in biological and material sciences since 1990. However, it is known that the resolution of two-photon imaging is adversely affected by the index mismatch induced spherical aberrations. Spherical aberration increases the focal volume and causes degradation of image resolution. The problem becomes worse as one image deeper into the specimen. In this work, we propose to use this intrinsic artifact to measure the refractive index in specimens of uniform refractive indices. Using the intensity profiles of standard refractive liquids as reference, we can compare the intensity profile of an unknown specimen of uniform refractive index with that of the reference to determine the refractive index of the unknown specimen.