Reference-Free Single-Point Holographic Imaging and Realization of an Optical Bidirectional Transducer

One of the fundamental limitations in photonics is the lack of a bidirectional transducerthat can convert optical information into electronic signals or vice versa. In acoustics or at microwave frequencies, wave signals can be simultaneously measured and modulated by a single transducer. In optics, however, optical fieldsare generally measured via reference-based interferometry or holography using silicone-based image sensors, whereas they are modulated using spatial light modulators. Here, we propose a scheme for an optical bidirectional transducerusing a spatial light modulator. By exploiting the principle of time- reversal symmetryof light scattering, two-dimensional reference-free measurement and modulation of optical fieldsare realized. We experimentally demonstrate the optical bidirectional transducerfor optical information consisting of 128 x 128 spatial modes at visible and short-wave infrared wavelengths.