Flexible terahertz devices are crucial for the advancement of wearable photonics and intelligent communication systems, but their practical deployment has been hindered by performance degradation under mechanical bending. In a significant step forward, a research team led by Professor Qingli Zhou from Capital Normal University and Professor Chen Ge from the Institute of Physics, Chinese Academy of Sciences, has developed flexible Te/PET films that serve as high-performance all-optical terahertz modulators. These films exhibit high modulation efficiency, picosecond response, low insertion loss, and robust tolerance to bending, marking a substantial improvement over existing flexible terahertz devices.
The new modulator leverages tellurium (Te) nanofilms deposited on polyethylene terephthalate (PET) substrates. Tellurium's unique helical chain structure, excellent optical response, high carrier mobility, and ambient stability make it an ideal material for terahertz modulation. When integrated with flexible PET, the Te nanofilms form mechanically robust and optically active films that can withstand deformation without significant loss of function. In tests, the device achieved a modulation depth of 50% on a picosecond timescale, with broadband operation and low insertion loss, even under low pump excitation.
One of the key findings of the study, published in Light: Advanced Manufacturing (DOI: 10.37188/lam.2026.086), is the device's mechanical stability. The transient terahertz photoresponse remained nearly unchanged after repeated bending cycles and under small bending radii. This stability is attributed to the mechanical tolerance of Te nanofilms and the flexibility of the PET substrate, which together maintain reliable terahertz modulation even when the device is deformed.
To demonstrate the practical potential of the device, the researchers integrated the measured terahertz modulation response into an artificial neural network (ANN) for image recognition. The recognition accuracy remained stable under different bending conditions, indicating that the mechanical robustness of the Te/PET device can be translated into reliable information processing. This suggests that flexible terahertz modulators could serve as front-end functional units for intelligent sensing and neuromorphic optoelectronic systems.
The scientists summarize their work: "We introduce flexible Te/PET films as a mechanically robust platform for ultrafast all-optical terahertz modulation. The device exhibits broadband response, low insertion loss, high modulation efficiency, and picosecond photoresponse, while maintaining stable performance under bending deformation." They add, "The stable terahertz response under different mechanical states enables reliable neural-network-based image recognition, suggesting the potential of Te-based flexible terahertz devices for intelligent sensing and wearable optoelectronic systems."
The research was supported by several funding sources, including the National Key R&D Program of China, the Postdoctoral Fellowship Program of CPSF, the Beijing Natural Science Foundation, and the National Natural Science Foundation of China. The findings provide a new device strategy for flexible terahertz modulators and offer guidance for the development of mechanically robust terahertz optoelectronic devices that can operate in complex deformation environments. For more information, visit the original source at https://doi.org/10.37188/lam.2026.086.
