Figure 8.

MPE simplified optical schemes. Descanned (red dot) and non-descanned (blue dot) schemes for 2PE microscopy. Due to the confinement of the excitation process when operating in non-descanned mode the collection efficiency in depth is increased as shown by the two side views from the very same thick scattering sample (Courtesy of Mark Cannel and Christian Soeller; image inset courtesy of Ammasi Periasamy).