Figure 2
From: Phase holograms for the three-dimensional patterning of unconstrained microparticles
Results of holographic acoustic fields. Each row represents the result from lens 1 (top), 2 (middle) and 3 (bottom). The columns are phase holograms (a,e,i) used to fabricate the lenses (b,f,j), simulation of desired image of pressure amplitude in the transverse xy-plane (c,g,k), and holography scan measurement of the acoustic fields at the desired image plane in the transverse xy-plane (d,h,l). In the acoustic pressure fields subplots, the solid white border outlines the piezoceramic active acoustic element. The field produced from lens 1 is equivalent to that of two sources with their acoustic axes separated by an angle 2θw (b) which outputs approximately a standing wave in the transverse direction (c,d). Lenses 2 and 3 produced five parallel axial planes as predicted by simulation (h,l). For lens 2, the outer planes are weakly formed and never achieve full illumination (h), while lens 3 produced five planes with outer planes slightly weaker than predicted by simulation (g,h).
