Image optical transmission

Figure 8.2a-c shows optical transmission images of organic microcrystals of perylene, anthracene, and pyrene, excited at a laser power of 1.7 nj pulse under similar excitation conditions as in Figure 8.1c. The bright spots <2 pm in diameter at the center of each microcrystal were areas irradiated with the NIR laser pulse.

Figure 8.2 Optical transmission images of pe lene (a), anthracene (b), and pyrene (c) microc stalsirradiated bythe NIRIaser scale bar 5 Xm. (d) Emission spectra offluorescence spots in the microcrystals of anthracene (dotted line), pyrene (broken line), and perylene (smooth line), (e) The dependence of the fluorescence...

Figure 8.4 (a) Scanning three-photon fluorescence image of pe lene microcrystals obtained by irradiation of the NIR pulse of 1260 nm with power 70 pj pulse scanning step 100nm. (b) Corresponding optical transmission image of the perylene crystals. 

An additional class of nonlinear optical effects is that of multi-photon absorption processes. Using these process, one can create excited states (and, therefore, their associated physical and chemical properties) with a high degree of three-dimensional (3D) spatial confinement, at depth in absorbing media. There are potential applications of multi-photon absorbing materials in 3D fluorescence imaging, photodynamic therapy, nonlinear optical transmission and 3D microfabrication. 

The next step was to improve the stability of the system and - even more importantly - to improve the transmission of the fiber tips. Metalization of the tip is the key and produces superior properties, such as a near-field spot of less than 20 nm [107-110]. Zeisel et al. reported that metalization led to optical transmission of a fiber higher than that of conventional fibers by several orders of magnitude [111]. The authors showed images based on the fluorescence of dye-labeled polystyrene spheres and noted that fast and irreversible photobleaching takes place in the near field with enhanced intensity. In addition, they reported on surface-enhanced near-field Raman spectra of cresol fast violet and p-aminobenzoic acid adsorbed on a (rough) silver substrate, exhibiting a signal-to-noise ratio of >10 [111]. 

Fig. 5 Cryosections of rat brain after administration of 45 and 200 mg of PBCA nanoparticles. Transmitted optical transmission images of the sections (40x). Nano green fluorescence created by the PMl-labeled nanoparticles. Willebrand endothelial cells stained with red fluorescent antibody (von Willebrand factor primary and anti-lgG secondary antibody with fluorescent label). Merge 40x and merge 63 x images merged from the green and red channels. Scale bars 100 mm [45]...

Fluorescence imaging and transmission UV microscopy of PP/0.5% Uvitex OB (optical brightener) were reported [63]. 

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