Photonic Band Gap Lattice Cavities

70801 Photonic band gap (PBG) structures, well known in solid state physics, have recently been proposed for applications as particle accelerators or high power microwave/millimeter wave sources. In spite of their relative ease of fabrication, practical issues such as power handling, tuning, cooling, and high order mode damping must be addressed. This project will examine PBG structures with single- and multiple-defect sites. The latter would have potential use in a multi-beam klystron and/or accelerating structure. In Phase I, the relation of the photonic band gap cavity to klystron and accelerator applications (including basic cavity properties, tuning, external power coupling, cooling, and detailed higher order mode properties) will be studied using numerical simulations. A PBG structure will be designed for subsequent testing in Phase II. Commercial Applications and Other Benefits as described by the awardee: As operating frequencies increase and device sizes decrease commensurately, the photonic band gap cavity should provide a significant advantage because of its ability to use "oversized" cavities and to isolate the desired mode from the higher order modes. Potential applications include high energy physics, especially future linear colliders. In addition, the oversized cavities also may be able to produce microwaves in the terahertz range, thereby impacting high-resolution medical imaging, radar, and high-speed communication.