Figure 3.

Experimental results. (a) Intensity of the phase conjugated beam at the back surface of the sample. The reconstruction beam refocuses back onto fluorescent bead. (b) Intensity of the same phase conjugated beam, after translating the sample over approximately 10 μm (same color scale as in a). The focus has disappeared because the microscopic scattering properties of the sample are different at this position. (c) Measured binary phase of the wavefront (at ${\text{CCD}}_1$). The raw data were filtered with a 1-pixel radius Gaussian filter to reduce measurement noise and then processed using Eq. 2. Scale bars are 10 μm (a and b) and 1 mm (c).