Spatial Super-Resolution

Future Challenges Single Molecule Detection, Higher Time Resolution and Spatial Super-Resolution in Femtosecond Microscopy... 

The optical layout for the measurement of biological samples (cells) is shown in Figure 29.3b. The sample was irradiated with co-linear IR and visible light beams. The transient fluorescence from the sample was collected from the opposite side by an objective lens. In this optical layout, the spatial resolution was determined by the objective numerical aperture (NA) and the visible fluorescence wavelength IR superresolution smaller than the diffraction limit of IR light was achieved. Here, Arabidopsis thaliana roots stained with Rhodamine-6G were used as a sample. We applied this super-resolution infrared microscope to the Arabidopsis thaliana root cells, and also report the results of time-resolved measurements. 

We have performed super-resolution infrared microscopy by combining a laser fluorescence microscope with picosecond time-resolved TFD-IR spectroscopy. In this chapter, we have demonstrated that the spatial resolution of the infrared microscope improved to more than twice the diffraction limit of IR light. It should he relatively straightforward to improve the spatial resolution to less than 1 pm by building a confocal optical system. Thus, in the near future, the spatial resolution of our infrared microscope will be improved to a sub-micron scale. 

We have also demonstrated picosecond time-resolved TFD-IR imaging of the vibration relaxation of Rhodamine-6G in Arabidopsis thaliana roots, and found an abnormally long-lived component of vibrational relaxation in a cell. This may result from a site dependence of vibrational relaxation within whole cells. These results indicate the possible utility of the two-color super-resolution infrared microscope in mapping specific IR absorptions with high spatial resolution, and the observation of dynamics in a non-uniform environment, such as a cell. By using this infrared super-resolution microscope, we will be able to visualize the structure and reaction dynamics of molecules in a wide range of non-uniform environments. 

Fig. 1 Photonic nanojet spatial intensity distribution, /= , inside and outside the 1.0 pm PS particle, illuminated by a laser pulse at A = 248nm, and (a) polarization parallel and (b) perpendicular to the image plane. The maximum intensity enhancement in calculations is about 60 for both regions, (c) Shows the intensity along z-axis. z = 1.0 is the position under the particle, (d) Super-resolution spot in atz=a, the tangent plane right under the particle.

To present our methodology, we describe the time-gated excitation-emission spectroscopic system in Section 32.3. 2D fluorescence spectroscopy acquiring excitation and fluorescence spectra has been widely used at research and diagnostic levels because of the high selectivity and simple configuration of the measurement system [12-16]. Here, we extended it to the 3D (Ex, Em, and x) system with a time-resolution of200 ps, by a combination of a spatially dispersed super continuum as the... 

Facial fractures are a common consequence of direct trauma, for example in a traffic accident. The complex anatomy of the facial structures requires super-position-free, detailed imaging. Therefore, helical CT in general is considered the standard imaging modality of facial fractures for characterization and classification. CT in at least two orthogonal planes, axial and coronal, is the standard examination to make a reliable and precise diagnosis for treatment planning (Philipp et al. 2003 Rosenthal et al. 2000). Narrow-collimation (0.6 mm-1.2 mm) axial acquisition yields a volume that allows creation of 2D and 3D reconstructions with very high spatial resolution (Fig. 25.6). Sections can be obtained in any plane. 

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