Truncated photonic crystal cavities with optimized mode confinement

Abstract

Optimization of a truncated, dielectric photonic crystal cavity leads to configurations that are far from truncated crystal cavities, and which have significantly better radiation confinement. Starting from a two-dimensional truncated photonic crystal cavity with optimal Q-factor, moving the rods from the lattice positions can increase the Q-factor by orders of magnitude, e.g., from 130 to 11 000 for a cavity constructed from 18 rods. In the process, parity symmetry breaking occurs. Achieving the same Q-factor with a regular lattice requires 60 rods. Therefore, using optimized irregular structures for photonic cavities can greatly reduce material requirements and device size.

Origin and reduction of wakefields in photonic crystal accelerator cavities

“…IV with an optimized cavity (from Ref. [10]) and compares these results with CLIC. Appendix A analyzes the performance of our numerical absorbers used in wakefield simulations.…”

“…In fact, for defect cavities, it may suggest the opposite. In a previous work, we discovered a 2D PhC-based cavity that strongly confines an accelerating mode without relying on the band gap principle [10]. In this paper, we simulate a 3D multicell adaptation of the 2D optimized cavity in Ref.…”

“…In this paper, we simulate a 3D multicell adaptation of the 2D optimized cavity in Ref. [10] and compare wakefields with the CLIC cavity. While wakefields in the optimized (no-band-gap) cavity are lower than those in the lattice-based PhC cavity and similar to those in CLIC, we observe a significant reduction in the confinement of the accelerating mode, induced by the presence of the irises.…”

“…Photonic crystals (PhCs) have recently attracted interest from the accelerator community [1][2][3][4][5][6][7][8][9][10][11][12] for the following reasons: (1) PhCs enable the construction of accelerator cavities using dielectric materials. (2) PhC cavities intrinsically provide a wakefield damping mechanism.…”

X-band photonic band-gap accelerator structure breakdown experiment

“…Recent advances in the study of photonic structures for accelerator applications include research on hybrid structures consisting of metallic and dielectric components [10,11]; research on quasicrystals [12]; research on disordered photonic structures [13]; research on truncated, optimized photonic structures [14]; and theoretical research on wakefields [15].…”