Researchers have developed a flexible all-optical terahertz modulator based on tellurium (Te) nanofilms grown on polyethylene terephthalate (PET) substrates, achieving high modulation efficiency, picosecond response, low insertion loss, and robust bending tolerance. The work, published in Light: Advanced Manufacturing, addresses a critical challenge in flexible terahertz devices: maintaining performance under mechanical deformation.
Flexible terahertz devices are increasingly important for wearable photonics, intelligent communication, flexible imaging, and sensing systems. Terahertz modulators are key components for controlling terahertz signals, but practical flexible devices often suffer from bending-induced structural changes, information loss, or signal interruption. The new Te/PET films offer a solution by combining the unique properties of tellurium—such as its helical chain structure, good optical response, high carrier mobility, and ambient stability—with the flexibility of PET substrates.
The research team, led by Professor Qingli Zhou from Capital Normal University and Professor Chen Ge from the Institute of Physics, Chinese Academy of Sciences, demonstrated that the Te/PET modulator achieves a high modulation depth of 50% on the picosecond timescale and an ultrasensitive response under low pump excitation. The device also exhibits broadband operation and low insertion loss, making it a promising candidate for flexible terahertz functional devices.
A key aspect of the study was the investigation of mechanical stability. The transient terahertz photoresponse remained nearly unchanged after repeated bending cycles and under small bending radii, indicating excellent mechanical tolerance. This stability is attributed to the mechanical robustness of the Te nanofilms and the flexibility of the PET substrate, which together maintain reliable terahertz modulation during deformation.
To assess the device's potential for intelligent applications, 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, demonstrating that the mechanical robustness of the Te/PET device translates 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 highlighted the significance of 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 added, "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 study was supported by several funding sources, including the National Key R&D Program of China, the Postdoctoral Fellowship Program of CPSF, Beijing Natural Science Foundation, and the Youth Innovation Promotion Association of CAS. The research was published with DOI 10.37188/lam.2026.086. Related information can be found at Chuanlink Innovations.
