Recently, researchers have achieved a major breakthrough in terahertz technology, developing a groundbreaking method to create and manipulate structured terahertz light beams with programmable spintronic emitters. This significant advancement holds promising implications for a wide range of applications including security, medical imaging, and communication.
Terahertz radiation, which falls between microwaves and infrared light on the electromagnetic spectrum, has long been recognized for its potential in various fields. However, effectively generating and controlling terahertz light has posed considerable challenges. The innovative technique developed by a team of researchers led by Prof. Zhensheng Tao, Prof. Yizheng Wu from Fudan University, and Prof. Yan Zhang from Capital Normal University represents a significant leap forward in this area.
The new method relies on programmable spintronic emitters based on exchange-biased magnetic multilayers, which are capable of converting laser-induced spin-polarized currents into broadband terahertz radiation. This breakthrough overcomes previous limitations by allowing precise and flexible programming of the magnetization pattern within the emitter. As a result, the researchers can now design and generate terahertz beams with complex polarization states, including spatially separated circular polarizations, azimuthal or radial polarization states, and even a full Poincaré beam.
The ability to produce Poincaré beams is particularly noteworthy, as these beams exhibit all possible states of light polarization within their cross-section. This unique property has wide-ranging applications, from generating special optical forces and achieving flat-top intensity profiles to enabling single-shot polarimetry measurements.
The research team successfully demonstrated the generation of various structured terahertz beams using their programmable emitters, with implications for advancing terahertz technologies across multiple fields. According to Prof. Zhensheng Tao, “Our findings pave the way for the development of novel terahertz devices with enhanced functionalities. The ability to manipulate terahertz light with such precision opens exciting possibilities for applications in spectroscopy, sensing, and communication.”
The study, titled “Flexible generation of structured terahertz fields via programmable exchange-biased spintronic emitters,” was authored by Shunjia Wang, Wentao Qin, Tongyang Guan, Jingyu Liu, Qingnan Cai, Sheng Zhang, Lei Zhou, Yan Zhang, Yizheng Wu, and Zhensheng Tao. The research was published on 8th July 2024 and can be referenced through DOI 10.1186/s43593-024-00069-3.
The study was made possible through funding from the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Shanghai Municipal Science and Technology Basic Research Project, and the National Key Research Program of China.
Overall, the breakthrough achieved by the research team represents a significant advancement in terahertz technology, offering unprecedented control over light beams with potential implications for a wide range of practical applications.