Phys.org June 14, 2024 Spin-torque driven critical spin dynamics, such as auto-oscillations, play the central role in many spin-based technologies. An international team of researchers (USA – UC Riverside, Johns Hopkins University, Germany, India, Ukraine) developed the theoretical framework of precessional auto-oscillations for ferromagnets with spin inertia. They discovered and introduced the concept of nutational auto-oscillations and demonstrated that they can become pivotal for future ultrahigh frequency technologies. They showed parallels between spin dynamics in ferrimagnets and inertial ferromagnets and derived an isomorphism that established a foundation for synergistic knowledge transfer between these research fields… read more. TECHNICAL ARTICLE
Tag Archives: THz technology
Anti-correlated plasma and THz pulse generation during two-color laser filamentation in air
Phys.org September 9, 2022 The THz generation efficiency and the plasma density generated by a filament in air have been found anti-correlated when pumped by two-color laser field. The plasma density near zero delay of two laser pulses has a minimum value, which is opposite to the trend of THz generation efficiency and contradicts common sense. The lower plasma density cannot be explained by the static tunneling model according to the conventional photocurrent model, but it might be attributed to the electron trapping by the excited states of nitrogen molecule. An international team of researchers (China, Japan) clarified the dominant […]
Carbon nanotube films open up new prospects for electronics
Nanowerk February 10, 2022 An international team of researchers (Russia, Finland) studied carbon nanotube films conductivity in the terahertz and infrared bands. Some of the films were made of nanotubes with lengths varying from 0.3 to 13 µm, while others were treated with oxygen plasma for 100 to 400 seconds and changed their electrodynamic properties in the process. They discovered that shortening tubes length (down to 0.3 µm) or exposing films to plasma (for longer than 100 s) leads to a drop in conductivity at low terahertz frequencies (< 0.3 THz). Exposure to plasma results in a larger number of […]
New chip hides wireless messages in plain sight
Science Daily November 23, 2021 Traditional encryption methods are challenging to scale for high-bandwidth, ultralow-latency applications. An alternative approach is to use physical-layer techniques that rely on the physics of signal propagation to incorporate security features without the need for an explicit key exchange. Ensuring security using directional, narrow-beam-like features of mm-wave/THz signals has proven to be vulnerable to passive eavesdroppers. An international team of researchers (USA – Princeton University, China) has developed a space-time modulation approach that ensures security by enforcing loss of information through selective spectral aliasing towards the direction of eavesdroppers, even though the channel can be […]