Fig. 4.

(A) Spectral power analysis of light sheet, confocal and widefield images. No technique has appreciable spectral power beyond 0.0025 nm⁻¹, corresponding to an ultimate optical resolution limit of 400 nm. (B) Simulated XZ slices of point spread functions for the oil immersion lenses used for widefield and confocal imaging at expanded gel sample depths of 0 and 10 microns. A significant aberration is shown at only 10 micron depth, halfway through the depth of a typical expanded cell, due to the significant difference in refractive index between gel and oil immersion. Scale bar 1 µm.