NONRECIPROCITY IN INTEGRATED OPTICAL AND MICROWAVE OPTOMECHANICAL BASED SYSTEMS
Abstract
High-Power Microwave (HPM) devices are used as oscillators and amplifiers of electromagnetic waves for a range of applications critical to air force operations; from communications to radar, from ECM to ECCM to active denial systems. For directed energy RF applications the conventional approach is to illuminate targets with high intensity EM waves. Using HPM devices to generate, short, high peak-power, pulses over a frequency range from MHz to GHz. Advances in our understanding of EM interactions with devices indicates that increased waveform diversity where a tailored low-power EM waveform amplified to high power may prove more effective operationally. Vacuum Electronic Devices (VEDs) remain the basis for many HPM technologies, where the generation of high-power EM waves is achieved by converting the kinetic energy of a charged particle beam into electromagnetic (RF/microwave) energy. In spite of the fields’ maturity, research into the coherent interaction of electromagnetic fields with charged-particle beams is currently experiencing substantial renewed interest. Driven by the spectacular progress in mastering the production of subwavelength electrodynamic structures, and our ability to produce and manipulate electron beams. Artificial electromagnetic materials are periodic composites where the response of the system to an EM-wave is determined by the micro-geometry of the composite rather than the material composition. The physical properties of these materials can be engineered to give a range of desirable EM properties, allowing scientists and engineers to explore a domain of EM wave interactions beyond that available with conventional materials. In particular this enables us to engineer a material to maximise the interaction between an EM wave and an electron beam creating a new class of VED. This research project has three themes, Theme (1) where we aim to exploit the ability to engineer the properties of artificial electromagnetic materials to create novel HPM VED based devices with increased waveform diversity. Creating artificial materials with low group velocities tailored to interact with sub relativistic electron beams. Utilizing dispersion engineering of these materials to create an arbitrary phase shift in an EM wave to remove the size dependence of VED based HPMs on the wavelength of operation enabling the creation of compact, lighter, RF amplifiers and oscillators. Theme (2) of this proposed research project is the use of active materials, where the materials properties can be modified in real time during device operation. We aim to use time-dependent artificial materials to investigate waveform frequency and amplitude diversity in HPM devices, an area identified of importance to the AFOSR in Announcement #FOA-AFRL-AFOSR-2019-0002. Examining the use of time-dependent artificial materials to amplify and modulate EM waves. Theme (3) focuses around developing cathodes that are the source of the electron beam. We aim to build upon existing research on the use of Carbon Nano Tubes (CNTs) as novel fiber array cathodes, to develop cathodes for the novel VED based HPM devices of theme (1).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA86552017002
Entities
People
- Rebecca Seviour
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Huddersfield