Figure 9.

3-D stack of SHG and TPF emission from the superficial zone of bovine articular cartilage. The 800 nm excitation is too long to excited collagen autofluorescence and hence narrow-band 400 nm imaging isolates collagen SHG whereas imaging the Stokes-shifted radiation reveals a spatially uncorrelated fibrous component which is identified as elastin. This appears to be the first consistent report of the existence of elastic fibers in the superficial zone, which confirms the power of the multi-photon technique. Reproduced from Yeh et al. (32) with permission. SHG, second harmonic generation.