Figure 5. Active optical elements and 3D holograms.

(a) A reconfigurable lens with a focal distance of 10 mm reconstructed with multiple images of the beam path (scale bar, 5 mm). (b) Beam waist measured along the path corresponding to the reconfigurable lens. (c) A 3D hologram of a coin recorded with interference of beams and its erasing process (scale bar, 1 cm). (d,e) Two different coins recorded after an erasing process. (f) Two coins superposed without an intermediate erasing process.