Information transfer around arbitrary opaque occlusions using programmed diffraction

We directly transfer optical information around arbitrarily-shaped, fully-opaque occlusions that partially or entirely block the line-of-sight between the transmitter and receiver apertures. An electronic neural network (encoder) produces an encoded phase representation of the optical information to be transmitted. Despite being obstructed by the opaque occlusion, this phase-encoded wave is decoded by a diffractive optical network at the receiver. We experimentally validated our framework in the terahertz spectrum by communicating images around different opaque occlusions using a 3D-printed diffractive decoder. This scheme can operate at any wavelength and be adopted for various applications in emerging free-space communication systems.