Parabolic mirror objective with high numerical aperture for imaging and spectroscopy at the nanometer scale

Summary form only given. Parabolic mirrors with high numerical aperture have been used as efficient light collection devices in the early cryogenic single-molecule work, but for microscopy and imaging they have been avoided due to poor off-axis imaging properties. However, in a stage scanning confocal microscope one can ensure that the optical focus is always on the optical axis. It is possible to fabricate a concave parabolic Al-mirror with an aperture close to one and hence it (1) can produce a tight diffraction limited spot, (2) can efficiently collect the radiation of a point light source in the focal spot, (3) has minimal chromatic aberrations since the rays are only deflected at one surface which is highly reflective over a large spectral range and (4) can be cooled down to cryogenic temperatures without loss of performance.