Flexible terahertz devices are crucial for wearable photonics and intelligent communication systems, but mechanical deformation often leads to signal loss or interruption. Researchers have now developed flexible Te/PET films that serve as ultrafast all-optical terahertz modulators, maintaining high performance even when bent. This innovation, published in Light: Advanced Manufacturing, offers a pathway to robust, flexible terahertz optoelectronics.
The new modulators, created by Professor Qingli Zhou from Capital Normal University and Professor Chen Ge from the Institute of Physics, Chinese Academy of Sciences, utilize tellurium (Te) nanofilms grown on polyethylene terephthalate (PET) substrates. Te’s unique helical chain structure provides excellent optical response, high carrier mobility, and ambient stability, making it an ideal material for terahertz modulation. When integrated with flexible PET, the films become mechanically robust and optically active.
The Te/PET devices achieve a modulation depth of 50% on a picosecond timescale with low insertion loss and broadband operation. They also exhibit an ultrasensitive response under low pump excitation, indicating high efficiency. Crucially, the devices maintain their performance under repeated bending and small bending radii, thanks to the mechanical tolerance of the Te nanofilms and the flexibility of the PET substrate.
To demonstrate practical utility, 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, proving that the mechanical robustness translates into reliable information processing. This suggests that flexible terahertz modulators could serve as front-end units for intelligent sensing and neuromorphic optoelectronic systems.
“We introduce flexible Te/PET films as a mechanically robust platform for ultrafast all-optical terahertz modulation,” the scientists stated. “The device exhibits broadband response, low insertion loss, high modulation efficiency, and picosecond photoresponse, while maintaining stable performance under bending deformation.” They added that the stable response under different mechanical states enables reliable neural-network-based image recognition, highlighting the potential for intelligent wearable optoelectronics.
The research was supported by several funding sources, including the National Key R&D Program of China, the National Natural Science Foundation of China, and the Youth Innovation Promotion Association of CAS. The full details are available in the paper with DOI 10.37188/lam.2026.086.
This development addresses a critical challenge in flexible terahertz technology, offering a new device strategy for modulators that can withstand complex deformation environments. As the demand for wearable and intelligent systems grows, such robust and efficient components will be essential for the next generation of terahertz applications.
