An imaging system, comprising: a stage configured to support a sample in an examination region, wherein the sample includes a photoluminescent component; an annular frame and an excitation filter; an illumination subsystem including a plurality of light sources mounted to the annular frame, at least one of the light sources being an excitation source configured to generate excitation light capable of inducing the photoluminescent component to produce photoluminescence, wherein the excitation filter is operatively disposed between the excitation source and the examination region and is configured to block passage of light that spectrally overlaps the photoluminescence; and a detection subsystem including an image detector configured to detect an image formed by photoluminescence induced by the excitation light, the detection subsystem also including an objective and an emission filter each operatively disposed in an optical path from the examination region to the image detector, wherein the optical path extends through a central opening defined by the annular frame, and wherein the emission filter is configured to prevent excitation light generated by the excitation source from reaching the image detector, wherein the objective includes an inner tube disposed at least partially inside an outer tube, characterized in that the imaging system further comprises an optical element configured to focus the light generated by the light sources onto the examination region of sample plane, wherein said optical element is formed by and/or located inside the outer tube, the plurality of light sources, or the annular frame and the plurality of light sources, are disposed at least partially in a tubular space defined between an exterior surface of the inner tube and an interior surface of the outer tube such that light generated by the plurality of light sources can travel along a respective optical path via the tubular space to the optical element which focuses the light onto the examination region of sample plane. a stage configured to support a sample in an examination region, wherein the sample includes a photoluminescent component; an annular frame and an excitation filter; an illumination subsystem including a plurality of light sources mounted to the annular frame, at least one of the light sources being an excitation source configured to generate excitation light capable of inducing the photoluminescent component to produce photoluminescence, wherein the excitation filter is operatively disposed between the excitation source and the examination region and is configured to block passage of light that spectrally overlaps the photoluminescence; and a detection subsystem including an image detector configured to detect an image formed by photoluminescence induced by the excitation light, the detection subsystem also including an objective and an emission filter each operatively disposed in an optical path from the examination region to the image detector, wherein the optical path extends through a central opening defined by the annular frame, and wherein the emission filter is configured to prevent excitation light generated by the excitation source from reaching the image detector, wherein the objective includes an inner tube disposed at least partially inside an outer tube, characterized in that the imaging system further comprises an optical element configured to focus the light generated by the light sources onto the examination region of sample plane, wherein said optical element is formed by and/or located inside the outer tube, the plurality of light sources, or the annular frame and the plurality of light sources, are disposed at least partially in a tubular space defined between an exterior surface of the inner tube and an interior surface of the outer tube such that light generated by the plurality of light sources can travel along a respective optical path via the tubular space to the optical element which focuses the light onto the examination region of sample plane.