CONFOCAL MICROSCOPY WITH AN INCREASED DETECTION APERTURE - TYPE-B 4PICONFOCAL MICROSCOPY

We show the point-spread function of a confocal microscope with an inc reased detection aperture. The increase in aperture is accomplished by coherent collection of the light from the specimen with two opposing objective lenses, i.e., type-B 4Pi confocal microscopy. We demonstrate experimentally its feasibility for detecting scattered or fluorescent ly emitted light. The 4Pi confocal point-spread functions are shown fo r constructive and destructive interference of the collected wave fron ts and are compared with the point-spread functions of comparable conf ocal microscopes.