Analysis of aberrations and performance evaluation of adaptive optics in two-photon light-sheet microscopy

Two-photon light-sheet microscopy (TP-LSM) system performance is greatly degraded by specimen-induced aberrations in illumination path, which limit the field of view, axial resolution and excitation efficiency of the system. Adaptive optics (AO) is an effective method for attenuating these effects. For the design and evaluation of an AO system, a comprehensive analysis of the effects of aberrations is needed. In this paper, a TP-LSM system is simulated, and new indexes based on integral intensity are introduced for the evaluation of an aberrated light-sheet. Then, the influences of each Zernike mode and random aberrations on the illumination path of the TP-LSM system are investigated with a numerical simulation method. Results show that high-order aberrations have little effect on the axial resolution and excitation efficiency of the system and only low-order components require correction. The random aberrations varied in strength with the depth of the specimens, so the number of corrected Zernike modes is variable. A general formula is generated for the estimation of the number of modes that should be detected and corrected under different aberrations and different numerical aperture of the objective. The results can provide important guidance in the design and evaluation of AO units for TP-LSM systems.