Two-point-separation in a sub-micron nonscanning IR super-resolution microscope based on transient fluorescence detected IR spectroscopy.

IR absorption of chemical species in microscopic objects such as biological cells cannot be measured by conventional IR microscopes, because of their low resolution. To overcome this problem, we developed a novel far-field IR super-resolution microscope employing transient fluorescence detected IR spectroscopy. The resolution of this microscope was shown to be 880 nm by measuring the image of 1 microm fluorescent beads. Furthermore, it succeeded in resolving beads located 1.4 microm apart from each other. This is considerably smaller than the diffraction limit of the applied IR light (3.4 microm). These results suggest the capability of our microscope to study sub-micron targets such as sub-cellular structures of biological cells.