Coherent synthesis of complex amplitude patterns using a photonic crystal surface-emitting laser

Recent progress in nanotechnology has enabled the development of highly functional semiconductor devices for embedding into wearable devices. We previously demonstrated an on-chip device that emits two-dimensional far-field patterns directly without lenses or scanning systems. However, its output pattern was stable or changed quasi-dynamically via switching, and continuous modulation was challenging. Here, we propose a continuously pattern-variable emitter that realizes complex-amplitude beam-pattern synthesis by embedding multiple pattern-projecting lasers into a single resonator and interfering their beams in the far field. We perform a proof-of-concept experiment successfully, demonstrate continuous changes in beam pattern between top-hat and Gaussian shapes, and realize continuous beam diameter change.