Figure 3.

a) The TPEF (green) identifies features in the mouse ovary tissue distinct from the SHG (red), which primarily shows the ordered collagen fiber regions. b) The ${\chi }_1={\chi }_{z^{\prime }{z}^{\prime }{z}^{\prime }}^{(2)}/{\chi }_{z^{\prime }{x}^{\prime }{x}^{\prime }}^{(2)}$ parameter shows two populations of collagen-related signals in the SHG channel, which are attributed to the presence of collagen type I (χ₁ = 1.2) and type III (χ₁ = 0.83). c) The ${\chi }_2={\chi }_{x^{\prime }{z}^{\prime }{x}^{\prime }}^{(2)}/{\chi }_{z^{\prime }{x}^{\prime }{x}^{\prime }}^{(2)}$, only includes one broad population that does not provide additional contrast for the collagen fibers in the χ-image of the tissue. d) A pseudo-colored image of χ₁. Reprinted with permission from ref [64], copyright 2015 John Wiley and Sons.