A novel high-resolution stage scanning confocal microscope for fluorescence
microscopy and spatially resolved spectroscopy with a high numerical apert
ure (NA approximate to 1) parabolic mirror objective is investigated. A spa
tial resolution close to the diffraction limit is achieved. As microscopic
fluorescent test objects, dye-loaded zeolite microcrystals (diameter approx
. 0.4 mum) and single fluorescent molecules were used. Confocal fluorescenc
e images show a spatial resolution of Deltax = 0.8.lambda both at room temp
erature and at 1.8 K. Imaging of a quasi-point light source and focusing by
the parabolic mirror were investigated experimentally and theoretically. D
eviations between the theoretical results for a perfect parabolic mirror an
d the experimental results can be attributed to small deviations of the mir
ror profile from an ideal parabola. (C) 2001 Optical Society of America.