Ultra-coherent meta-emitter tailors arbitrary thermal wavefront.

Abstract

Conventional coherent light-field manipulation techniques inherently conflict with the spatiotemporal incoherence of thermal radiation sources. While recent advances in thermophotonics have facilitated directional thermal emission, arbitrary thermal wavefront control-a cornerstone for advanced functionalities like focusing and holography-remains an unaddressed challenge. Here, we report a generalized recipe of designing meta-emitters with lossy and lossless outer boundaries, that enables thermal emission with arbitrarily tailored wavefront. Lossy and lossless surfaces on two sides of the meta-emitter are synergistically coupled by a single-mode waveguide, transforming incoherent thermal photons to coherent surface waves for wavefront shaping functionalities. Designer surface mode of meta-emitter permits the independent optimization of photon lifetime and propagation length, thus enabling scalable spatial coherence engineering. For the proof of concept, we experimentally demonstrate near-diffraction-limited self-focusing emission, quasi-two-dimensional (quasi-2D) high-quality thermal holography without speckle noise and spatial-multiplexed holography. Coupling optimization further suggests that spatial coherence exceeding 1000λ₀ are achievable. Our proposed meta-emitter establishes a paradigm-shifting framework to integrate stochastic thermodynamic emission with precision photonic engineering, opening avenues for information-rich thermal radiation technologies.