Femtosecond fluorescence up-conversion microscope

FIGURE 3.3 Schematic diagram of the femtosecond fluorescence up-conversion microscope. (From Fnjino, T. and Tahara, T. J. Phys. Chem. B 107 5120-5122, 2003. Used with permission)... 

As described in the previous section, the femtosecond fluorescence up-conversion microscope enabled us to visualize microscopic samples based on position-depen-dent ultrafast fluorescence dynamics. However, in the imaging measurements using the fluorescence up-conversion microscope, XY scanning was necessary as when using FLIM systems. To achieve non-scanning measurements of time-resolved fluorescence images, we developed another time-resolved fluorescence microscope. 

The time-resolved techniques that are usually used for FLIM are based on electronic-basis detection methods such as the time-correlated single photon counting or streak camera. Therefore, the time resolution of the FLIM system has been limited by several tens of picoseconds. However, fluorescence microscopy has the potential to provide much more information if we can observe the fluorescence dynamics in a microscopic region with higher time resolution. Given this background, we developed two types of ultrafast time-resolved fluorescence microscopes, i.e., the femtosecond fluorescence up-conversion microscope and the... 

The second example of the application of fluorescence up-conversion microscope is imaging of organic microcrystals based on ultrafast fluorescence dynamics (femtosecond fluorescence dynamics imaging) (Fujino et al. 2005a). In this measurement, the site-specific energy transfer rate in a tetracene-doped anthracene microcrystal was measured, and the crystal was visualized based on the observed local ultrafast dynamics. 

Here we first describe the ultrafast fluorescence microscope, which nses the fluorescence up-conversion method. This microscope simnltaneonsly achieves femtosecond time resolution and snbmicron space resolution (Fnjino and Tahara 2003, 2004). 

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