Binary-intensity-synthetic digital optical phase conjugation for multifocal control through scattering media.

Controlling light to multiple focal locations through complex scattering media is becoming increasingly significant in various realms. Although wavefront shaping (WFS) has been demonstrated as a promising solution to counteracting optical scattering, current WFS methods for multifocal control through scattering media suffer from low focal quality, extensive measurements, or complexity of system configurations and signal reconstructions. Here, we report a WFS concept, called binary-intensity-synthetic digital optical phase conjugation (BIS-DOPC), to mitigate these drawbacks. The BIS-DOPC records a single on-axis speckle interferogram of the scattered light originating from a movable guidestar and superimposes the interferograms from multiple predefined guidestar locations to create an "intensity-synthetic" interferogram. We find that the light with a wavefront corresponding to a binarized version of the synthetic intensity map converges to all the guidestar locations through scattering media. The good focal quality, reduced measurement requirements, and simplicity of system configuration, data acquisition, and processing make BIS-DOPC an attractive solution for multifocal control through scattering media.