Figure 1.

The Schematic of the presented approach for light control between two turbid layers. (a) The schematic of our experimental setup. The scenario we consider here is a light-transparent space confined by two turbid layers. The sample beam (green path) is focused by a lens to form a quasi-point source on the internal surface (right surface) of the front turbid layer (left one), which is used as a reference spot for pre-characterization of the back turbid layer (right one). A spatial light modulator is imaged onto the external surface (right surface) of the back turbid layer (imaging lens not shown here, see Fig. S1 in Supplementary Information). The played-back reference beam (red path) is modulated by the SLM according to the applied phase map, which is a stacked one consisting of three parts shown in (b), (c) and (d), respectively. (b) The conjugated phase map of the sample beam. (c) A quadratic phase map which is used to cancel out the quasi-spherical wave emitted from the quasi-point source. (d) A pre-calculated phase map for the intended intensity pattern (presented by the smiling face). The modulated reference beam can be seen as a loaded carrier wave with the phase-conjugated wave and the quadratic wave together as the carrier, and the pre-calculated wavefront as the load. The carrier wave suppresses the turbidity of the back turbid layer and thus can transport the pre-calculated wavefront through this layer, which would generated/projected the intended intensity pattern.