In a groundbreaking study, researchers from Graphic Era Deemed to be University in Dehradun, India, have delved into the fascinating world of terahertz radiation and its interaction with surface plasmons. The research, led by Associate Professor Pawan Kumar, focuses on the excitation of tunable THz surface plasmons in a symmetrical metal-air-metal structure using a relativistic electron beam.
THz radiation, with frequencies ranging from 0.1 to 10 THz, is a novel type of radiation that has garnered significant attention due to its unique properties. It possesses both quantum and electronic properties of materials and is nonionizing, allowing it to penetrate through most polymeric materials easily. This makes THz radiation a promising tool for various applications, including medical diagnostics and photonics devices.
The researchers investigated the properties of plasmons in the THz frequency range that arise when a beam passes through the gap between two metallic plates. This structure supports the field of guided electromagnetic modes or SPs, which have a minimum value at the middle of the gap. Consequently, an electron beam passing through this air gap experiences a converging force, enabling it to propagate without any divergence.
One of the key findings of the study is that these SPs have a lower phase velocity than the free space velocity of photon. This allows them to be excited by a moving relativistic electron beam via Cherenkov interaction. When a relativistic electron beam moves through the air gap, it resonantly excites the SPs in the THz frequency range. These THz-SPs are then transformed into coherent THz radiation when they pass over a periodic structure.
The proposed metal-air-metal structure opens up new possibilities for designing compact sources of coherent and tunable THz radiation generation in a broad spectrum regime. By leveraging the properties of SPs and their interaction with relativistic electron beams, researchers can develop advanced THz radiation sources that offer improved control and tunability.
The study's findings have significant implications for various fields, including medical diagnostics and photonics devices. THz radiation's ability to penetrate through polymeric materials and its nonionizing nature make it a valuable tool for medical imaging and diagnostics. Additionally, the development of compact and tunable THz radiation sources could revolutionize the field of photonics, enabling the creation of novel devices and applications.
Associate Professor Pawan Kumar, a theoretical physicist with expertise in fundamental plasma physics, laser-plasma interaction, fusion research, plasmonics, and compact radiation sources, led the research team. The study's publication in the prestigious journal Physics highlights the significance of the findings and their potential impact on the scientific community.
As research in the field of THz radiation and surface plasmons continues to advance, the development of compact, tunable, and coherent THz radiation sources holds immense promise. The study conducted by the researchers at Graphic Era Deemed to be University serves as a crucial step towards unlocking the full potential of THz radiation and its applications in various domains, paving the way for future innovations in medical diagnostics, photonics devices, and beyond.
