A laser scanning microscope having a laser source for fluorescence excitation; a scanning mirror arrangement for scanning a specimen and scanning optics for generating a diffraction-limited reference image plane as a first intermediate image plane; an optical system for demagnified imaging of the reference plane in a second intermediate image plane; an axially slideable mirror in the second intermediate image plane; a beam splitter arrangement between the reference image plane and the optical system; and a tube lens and a first microscope objective for imaging of the reference image plane into a specimen. The imaging of the image is effected with a magnification of M≠n/n′ and/or a magnification of the second intermediate image plane into the specimen according to the equation M = y ′ y = n n ′ ⁢ ξ , with |ξ|≠1, and/or the focal plane of the laser deviates from the axial position of the axially movable mirror across its scanning area in the second intermediate image plane.