Figure 2

SHG intensity ISHG-λIII linearly decreases with an elevation of λIII. (a–l) Typical SHG images of collagen gels captured in backward (a–f) and forward (g–l) photomultiplier tubes. The λIII was changed for each gel. Scale bar = 100 µm for all images. (m) Plot showing the relationship between SHG light intensity and λIII. (n) Forward/backward ratio of SHG light intensity plotted against λIII.