Aberration correction in coherence imaging microscopy

Coherence imaging microscopy enables a high-resolution optical microscopy with an infinite depth of field. For that purpose, the complex coherence function in the pupil plane of the microscope objective is determined, from which the spatially incoherent object structure is reconstructed. Using an image inverting interferometer, it is possible to measure the complex coherence function with a high spatial resolution. Phase aberrations caused by the imaging optics or the specimen itself influence solely the phase of the coherence function, not its amplitude. As a consequence, a purely numerical correction of these aberrations afterwards is possible. Compared with other procedures like deconvolution approaches, for instance, clearly stronger aberrations can be corrected and the signal-to-noise ratio is not decreased. Furthermore, different aberrations depending on depth and/or position (e.g. spherical aberrations) can be corrected. In addition to the principle of function, we will discuss the possibilities and limitations of this kind of aberration correction.