5-D fluorescence imaging using an all-solid-state diode-pumped laser system

Summary form only given. Fluorescence is widely used in biomedicine and other applications both to track specific fluorophores and study anatomical features. Fluorescence lifetime measurements add functional information because they are dependent on the local environment of the fluorophores (e.g. oxygen, [Ca/sup 2+/], pH etc.) e.g. Fluorescence Lifetime Imaging (FLIM) is particularly exciting since it can exploit this feature to provide non-invasive functional/diagnostic imaging. Complementary functional information may be obtained using spectrally-resolved fluorescence imaging. In order to acquire both spectral and lifetime information from an optical section in a reasonable time, it is preferable to acquire-all the image information in parallel, rather than to scan pixel by pixel at different emission wavelengths. We report, for the first, time to our knowledge, the combination of depth-resolved FLIM, by structured illumination, and hyperspectral imaging, thus realising 5-D fluorescence imaging. The recent development of user-friendly and relatively portable ultrafast laser technology and the availability of ultrafast gated optical image intensifiers (GOI´s) mean that this technology can be readily applied to almost any optical imaging modality including microscopy and endoscopy. We report a whole-field optically sectioning. fluorescence imaging system with fluorescence lifetime and spectral contrast, based on a GOI and an all-solid-state diode pumped Cr:LiSAF oscillator-amplifier system. Diode-pumped laser technology potentially provides a portable and relatively inexpensive FLIM instrument.