Concept for laterally resolved Fourier transform infrared spectroscopy below / beyond the diffraction limit - applications for optical (but also electronic) fast readout of ultra-small memory cells in the form of luminescent quantum wells - as well as in biology / crystallography

摘要

The invention relates to a basic concept for a computer-assisted optical “non-scanning” color microscopy (spatially resolved optical spectroscopy) method, which should enable a lateral resolution which is better than the usual diffraction limit, especially under certain conditions in particular the degree of mutual (inc) coherence of the light components emitted by small sample details and / or in particular if the sample topography / geometry (but not the color details) are known in advance, e.g. B. using scanning probe microscopy. It is therefore proposed that the lateral resolution limit for an optical color image could be overcome by looking at the (colored) diffraction image (i.e. the 2-dimensional diffracted intensity profile) of a small sample (e.g. in the simplest case a double slit or two tiny dark ones Slices or an optical grating with distance / grating constants smaller than λ / 2) recorded directly or in the focal plane of a microscope objective using a (color-sensitive) high-resolution light pixel sensor matrix (e.g. a CCD camera) and then this diffracted (Spatial Frequency Space) - (Color) image transformed back into a spatial color image using numerical computer software instead of allowing this spatial image to build up in the image plane in the far field of a microscope lens. (However, this conventional optical spatial image can of course be recorded simultaneously in order to obtain additional information about the sample.) Depending on the distance from the sample in which this diffracted color image was recorded, this numerical reverse transformation / recalculation software must be suitable Equations are used, namely essentially the Fourier transformation in the Fraunhofer (far field / plane wave) approximation or the Fresnel equations in the spherical wave approximation closer to the sample. For very small, in particular nanometric, metallic sample details, scattering theory and non-linear optics would also have to be considered. The smaller the sample details are and the more of these one finds within sample surface elements of roughly the size (λ / 2) 2 beyond the lateral resolution limit, the more topographic / geometrical preliminary information about these sample details would then obviously be for a successful back calculation of the diffracted Picture may be necessary. In a preferred embodiment, it is proposed to carry out the spectroscopy part of the concept according to the invention using the FTIR method.