Figure 2.

Principles of sound‐speed programmable holography. a) The acoustic waves generated by the transducer are modulated by the hologram and travel through a changeable fluid into the acoustic window, which patterns microparticles by concentrating them at the maximum acoustic intensity locations. b) Images corresponding to different medium sound speeds (and transfer functions) are encoded in a hologram. For the same incident wave, different images can be generated on the plane at z according to the medium sound speed. Supporting Information Figure S1 (Supporting Information) shows the dimensions and photos of the device.