A high numerical aperture parabolic mirror as imaging device for confocal microscopy

We explore the diffraction limited focusing and confocal imaging properties of a high NA parabolic mirror for confocal imaging and spectroscopy of nan oparticles and single molecules. Vector field calculations of the electric fields near focus for both linear and radially polarized illumination are d iscussed and show that the optical field can be similar tightly focused as in the case of a high NA objective lens. Furthermore they show that a high NA parabolic mirror allows an easy orientation of the polarization of the i lluminating light in all spatial directions. The simulation of confocal ima ging of single molecules is discussed and yields, that the use of radially polarized excitation light gives an easy access to their orientations. (C) 2001 Optical Society of America.