High-resolution three-dimensional tomographic diffractive microscopy of transparent inorganic and biological samples

We have developed a tomographic diffractive microscope, equipped with a fluorescence confocal scanner. We measure experimentally the lateral resolution using an edge method and by comparing tomographic images of the same samples with wide-field and laser scanning confocal microscopy images; a scanning electron microscope image serves as a reference. The experimental resolution is shown to be to about 130 nm, or lambda/(3.5 NA). This instrument also permits one to measure 3D, complex index of refraction distributions, a quantity that is not accessible to conventional microscopes, and we show how this feature may be used to observe KCI crystals, absorption of which is very weak. (c) 2008 Optical Society of America OCIS codes: 180.6900, 090.1995, 110.6960.