Abstract: A controller for an imaging device is configured to control an optical detection unit to receive fluorescence light emitted by first and second fluorophore species excited by first and second excitation light, respectively, to separate the fluorescence light into at least two spectral detection channels corresponding to two wavelength bands, respectively. A first wavelength band includes an emission spectrum of the first fluorophore species. A second wavelength band includes an emission spectrum of the second fluorophore species. The controller is further configured to control the optical detection unit to detect photon arrival times of the fluorescence light relative to light pulses of the second excitation light, to determine a temporal correlation between the light pulses and the photon arrival times, and to determine a first number and a second number of photons received in the first spectral detection channel and/or the second spectral detection channel based on the temporal correlation.

Abstract: A microscope has an aperture arrangement that, in order to limit the dimension of a light beam, comprises an aperture opening. The size of the aperture opening is adjustable with the aid of a first aperture member and a second aperture member. At least one of the two aperture members is movable relative to the other aperture member. The aperture members are spaced apart from one another when the aperture opening is closed.

Abstract: A microscope (10) has an aperture arrangement (29) that, in order to limit the dimension of a light beam (41), comprises an aperture opening (37). The size of the aperture opening (37) is adjustable with the aid of a first aperture member (32) and a second aperture member (34). At least one of the two aperture members (32, 34) is movable relative to the other aperture member (32, 34). The aperture members (32, 34) are spaced apart from one another when the aperture opening (37) is closed.