Research Projects

Quantum orbital angular momentum (OAM) beam sources at microwave frequencies find potential applications in mega-scientific projects for understanding the photonic interaction with low-energy matter and thereby exploring quantum phenomena like photon entanglement. These explorations would lead towards the successful development of quantum communication at microwave frequencies. Generation of quantum OAM beam is different from statistical OAM beam, where, SPP plates or metasurfaces are generally used at microwave frequencies. Preliminary experimental research on quantum beams confirms that radiation caused by the gyrating electron beam in the interaction cavity of the gyrotron produces a highly coherent quantum OAM beam at microwave frequencies. So far gyrotron development has been carried out for applications including plasma heating, and medical spectroscopy, where Gaussian-like output beams are preferred for efficient operation. However, for quantum OAM beam generation, the output beam of the gyrotron should be in whispering gallery mode (higher order circular cavity mode). This poses challenges in the entire design procedure of gyrotron including interaction cavity and output coupling assembly. To the best of PI’s knowledge, gyrotron development for generating highly coherent quantum OAM has not been carried out. Thus, in the proposed research, design studies of the gyrotron will be reinvestigated for the efficient multi-band (X/K/Ka) generation of OAM beams with a power level of 50 kW. These frequency bands are the favorable choice of exploring quantum OAM properties of microwave photons. The proposed work includes the design of major sub-assemblies of the gyrotron including the interaction cavity, output coupling system along with circular horn antenna. Design challenges such as mode competition in the interaction cavity and mode conversion across the output coupling assembly at desired bands will be addressed while carrying out the design. To achieve compactness in the overall gyrotron design, higher cyclotron harmonics of operation will be considered. Interaction cavity assembly will be designed through the self-consistent theory of gyrotrons and particle-in-cell simulation will be carried out using CST studio suite to verify the design. The output coupling assembly, along with the circular horn, will be designed using the CST studio suite. In addition, interaction circuit along with the output coupling assembly will be fabricated and cold-test analysis will be carried out. The proposed research is in line with the Mega-Science-Vision 2035 report. The proposed research outcomes will support the Indigenous development of quantum OAM sources and aid towards the exploration of microwave quantum phenomena.

Gyrotron, Quantum OAM, High-Power Microwaves