Methods for imaging a sample using fluorescence microscopy, systems for imaging a sample using fluorescence microscopy, and illumination systems for fluorescence microscopes. In some examples, a method includes positioning the sample such that a plane of interest of the sample is coplanar with a focal plane of a detection objective of a microscope. The method includes positioning a paraboloidal mirror around the sample such that a focal point of the paraboloidal mirror is coplanar with the focal plane of the detection objective and the plane of interest of the sample. The method includes directing a beam of annularly collimated excitation light on the paraboloidal mirror to focus a disc of light on the sample and thereby to provide 360 degree lateral illumination of the sample. The method includes imaging the sample through the detection objective.