There was only one road through the wood, and the two finger-posts both pointed along it.
Through the Looking-Glass
With the exception of the setups in Figure 7.24 and Figure 7.30, all the optical systems in the previous chapter have been basically Denisyuk configurations. Figure 7.24 showed one method of making a laser transmission hologram with a single laser beam, with part of the beam illuminating the object and part going past the object to form a reference beam, effectively producing two beams without the need for a beamsplitter or any additional mirrors. Figure 7.30 demonstrated a similar principle applied to a 360° setup. Those configurations are very limited and in most cases are ...