Ultrafast thermal metamaterials enable programmable infrared emission and display technology.

Researchers developed a reconfigurable thermal metamaterial pixel array utilising graphene field-effect transistors to achieve ultrafast, multicoloured infrared emission. This decoupled thermal generation from emission design, enabling precise spatial, temporal, and spectral control, demonstrated by displaying alphabetical letters via progressive scanning.

The manipulation of thermal radiation, typically a diffuse and slow process, presents a considerable challenge in the development of advanced infrared technologies. Researchers are now demonstrating increased control over this phenomenon through innovative material design and device architecture. A team led by scientists at Carnegie Mellon University, comprising Yibai Zhong, Xiu Liu, Zexiao Wang, Tianyi Huang, Jingyi Zou, Sen Lin, Xiao Luo, Zhuo Li, Rui Cheng, Xu Zhang and Sheng Shen, detail their work in a new study published in a recent journal. Their research focuses on reconfigurable ultrafast thermal metamaterial pixel arrays fabricated using dual-gate graphene transistors, a system enabling precise spatial, temporal and spectral control of emitted infrared radiation.

Reconfigurable Metamaterial Array Enables Ultrafast Control of Thermal Emission

Researchers have demonstrated a reconfigurable thermal metamaterial pixel array capable of manipulating infrared radiation with unprecedented speed and precision. The device integrates active metasurfaces with dual-gate graphene field-effect transistors (Gr-FETs) to dynamically control thermal emission across spatial, temporal, and spectral dimensions.

Traditional thermal emitters typically suffer from slow response times and emit broadband, diffuse infrared radiation. This new technology overcomes these limitations by decoupling the generation of heat from the design of emission. This separation allows for precise programming of thermal output, opening avenues for advanced infrared technologies.

The core of the innovation lies in the pixel design. Each pixel incorporates a Gr-FET functioning as both a microheater and an electrical switch. This dual functionality is achieved through a novel dual-gate control scheme. One gate (VG,PU) regulates the power delivered to the pixel, while the second (VG,MM) modulates the central metamaterial element, controlling thermal emission. Simulations and experimental data confirm precise control over power distribution and pixel temperature via this mechanism.

Experimental characterisation reveals high carrier mobility within the graphene – 1100 cm²/V·s – indicating material quality and efficient operation. The team demonstrated a 3-dB cutoff frequency of approximately 187 kHz, representing the speed at which a single pixel can switch between thermal states. Thermoreflectance measurements corroborate these dynamic response characteristics.

A fabricated three-by-three pixel array successfully displayed alphanumeric characters through progressive scanning, demonstrating the potential for complex pattern generation. This capability suggests applications in infrared camouflage, dynamic thermal management of electronic devices, and advanced thermal sensing. The decoupling of heating and emission design allows for narrowband, multicolour infrared emission, a feature not readily achievable with conventional thermal emitters.

Future work focuses on scaling the array to larger dimensions and higher resolutions to enhance display capabilities. Researchers are also investigating alternative metasurface designs and materials to optimise emission characteristics and expand the spectral range of control. Integration with advanced control algorithms and machine learning techniques promises to unlock more sophisticated thermal signature manipulation and adaptive thermal management strategies. Reducing power consumption and improving long-term device stability will be crucial for practical implementation.