Flexible terahertz devices are crucial for the advancement of wearable photonics and intelligent communication systems, yet they face a significant challenge: mechanical deformation can degrade performance, leading to information loss and signal interruption. In a new study published in Light: Advanced Manufacturing, researchers have introduced tellurium (Te) nanofilms grown on polyethylene terephthalate (PET) substrates as a solution, creating flexible all-optical terahertz modulators that exhibit high modulation efficiency, picosecond response, low insertion loss, and robust bending tolerance.
The research, led by Professor Qingli Zhou from Capital Normal University and Professor Chen Ge from the Institute of Physics, Chinese Academy of Sciences, demonstrates that Te nanofilms are an ideal material platform for this application. Te's unique helical chain structure, good optical response, high carrier mobility, and ambient stability make it well-suited for terahertz modulation. By integrating these films with flexible PET substrates, the team developed mechanically robust and optically active films that can withstand bending without significant performance loss.
The device achieved a modulation depth of 50% on the picosecond timescale with low insertion loss, and it responded sensitively to low pump excitation. These characteristics indicate that Te/PET films provide a solid foundation for flexible terahertz functional devices. Importantly, the researchers tested the mechanical stability of the device under various bending conditions, finding that the transient terahertz photoresponse remained nearly unchanged after repeated bending cycles and even at 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 during deformation.
To explore the practical applications of this technology, the team integrated the measured terahertz modulation response into an artificial neural network (ANN) for image recognition. The recognition accuracy remained stable under different bending conditions, demonstrating that the mechanical robustness of the Te/PET device can be translated into reliable information processing. This result suggests that flexible terahertz modulators could serve as front-end functional units for intelligent sensing and neuromorphic optoelectronic systems.
In their summary, the scientists state, "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 offer a new strategy for developing flexible terahertz modulators and provide guidance for creating mechanically robust terahertz optoelectronic devices that can operate in complex deformation environments. For more details, refer to the original source at https://doi.org/10.37188/lam.2026.086.
