How do multiphoton optics differ from confocal? In any laser scanning microscope the beam is focused into a cone where the intensity of illumination a
{"Image DocumentName": "How do multiphoton optics differ from confocal?", "Image ImageDescription": "In any laser scanning microscope the beam is focused into a cone where the intensity of illumination above or below the focal plane is proportional to the square of the distance from focus and absorption is directly proportional to intensity. However, in the 2-photon case, because of the need for two photons to arrive in a short time interval, absorption is proportional to the square of the intensity and falls off very rapidly away from the focus (according to an inverse fourth-power rule). The fall-off is even more rapid with 3-photon and higher order processes. Analysis (Williams et al.) yields the perhaps unexpected result that, provided the illuminated volume is uniformly filled with fluorophores, the total fluorescent emission signal strength is independent of the numerical aperture of the objective lens. Unlike confocal microscopy, multiphoton imaging is quite effective with low-magnification lenses of moderate numerical aperture, provided wide-angle detection is used.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}