How to Build an SHGApparatus 41
• e capability to estimate the mean orientation and/or the spatial distribution of the emitters
contained in the focal volume with respect to the optical axis by measuring the ratio between
forward and backward scattered light (LaComb etal., 2008, Nadiarnykh etal., 2010). In fact, as
reported in Figure 2.13, the front-to-back emission ratio (F/B) depends on the angle between the
emitter and the optical axis with a monotonic behavior.
2.3.3 Optical Filtering
Optical ltering is a crucial point for an SHG microscope, since the power density of the excitation is
extremely high in comparison to the signals to be detected. Filtering is commonly achieved by using
three optical elements:
• A dichroic mirror for ...