ABSTRACT
Figure 8.3 showed one method of making a laser transmission hologram with part of the laser beam illuminating the object and part going directly past it to form the reference beam, effectively producing two beams without the need for a beamsplitter. This configuration is suitable only for rim-lit or translucent subject matter. This chapter shows how you can get over this limitation, and produce a whole family of holographic setups based on similar geometrical principles. As this family of configurations seems to need a name I have coined the general term bypass holograms. Because the geometry is simple, and both parts of the laser beam travel through much the same space, you don’t need a rigorous stabilization system. You can make all the types of hologram described in this chapter literally on the kitchen table, provided you have the individual optical components fastened down to a paving slab or an optical breadboard.
