Structured coherent thermal emission from non-Hermitian metasurfaces

Area of Science:

• Optics and Photonics
• Metamaterials
• Thermal Engineering

Background:

• Metasurfaces offer control over thermal radiation properties like directionality and polarization.
• Achieving coherent thermal emission with vectorial polarization or structured light remains a significant challenge.

Purpose of the Study:

• To introduce a non-Hermitian thermal meta-emitter capable of generating vectorial-polarized thermal emission.
• To overcome trade-offs between coherence, spectral selectivity, and polarization control in thermal emitters.

Main Methods:

• Utilizing perturbation-induced Brillouin-zone folding to couple Fabry-Perót modes to bound states in the continuum.
• Exploiting non-Hermitian dynamics near exceptional points for dispersion and loss engineering.
• Engineering a sharp variation of the radiative Q-factor in k-space.

Main Results:

• Experimental generation of highly directional, rainbow-free, vectorial-polarized thermal emission.
• Observation of doughnut-shaped narrowband thermal emission in the 3-5 μm atmospheric transparency window.
• Demonstration of high spectral purity, extreme directionality, and distinct vectorial polarizations.

Conclusions:

• The developed non-Hermitian meta-emitter successfully sculpts thermal fluctuations into coherent vectorial-polarized beams.
• This work establishes a powerful platform for advanced control over thermal radiation.
• The findings pave the way for novel applications in thermal management and optical devices.